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Engineering Mechanics: Statics and Dynamics

R. C. Hibbeler

Chapter 13

Kinetics of a Particle: Force and Acceleration - all with Video Answers

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Chapter Questions

06:30

Problem 1

The 6 -lb particle is subjected to the action of its weight and forces $\mathbf{F}_{1}=\{2 \mathbf{i}+6 \mathbf{j}-2 \mathbf{k}\}$ lb, $\mathbf{F}_{2}=$ $\left.\left\{t^{2} \mathbf{i}-4 t \mathbf{j}-1 \mathbf{k}\right\} \| \mathbf{b}, \text { and } \mathbf{F}_{3}=\{-2 r\}\right\}$ Ib, where $t$ is in
seconds. Determine the distance the ball is from the origin 2 s after being released from rest.

Supratim Pal
Supratim Pal
Numerade Educator
07:02

Problem 2

The two boxcars $A$ and $B$ have a weight of 20000 th and $30 ~ 000$ Ib, respectively. If they are freely coasting down the incline when the brakes are applied to all the wheels of car $A,$ determine the force in the coupling $C$ between the two cars. The coefficient of kinetic friction between the wheels of $A$ and the tracks is $\mu_{k}=0.5 .$ The wheels of $\operatorname{car} B$ are free to roll. Neglect their mass in the calculation. Suggestion: Solve the problem by representing single resultant normal forces acting on $A$ and $B$, respectively.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
04:46

Problem 3

If the coefficient of kinetic friction between the $50-\mathrm{kg}$ crate and the ground is $\mu_{2}=0.3,$ determine the distance the crate travels and its velocity when $t=3 \mathrm{s}$ The crate starts from rest, and $P=200 \mathrm{N}$.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
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Problem 4

If the 50 -kg crate starts from rest and achieves a velocity of $v=4 \mathrm{m} / \mathrm{s}$ when it travels a distance of $5 \mathrm{m}$ to the right, determine the magnitude of force $\mathbf{P}$ acting on the crate. The coefficient of kinetic friction between the crate and the ground is $\mu_{k}=0.3$.

Lien Le
Lien Le
Numerade Educator
08:59

Problem 5

If blocks $A$ and $B$ of mass $10 \mathrm{kg}$ and $6 \mathrm{kg}$ respectively, are placed on the inclined plane and released, determine the force developed in the link. The coefficients of kinetic friction between the blocks and the inclined plane are $\mu_{A}=0.1$ and $\mu_{B}=0.3 .$ Neglect the mass of the link.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
04:27

Problem 6

If blocks $A$ and $B$ of mass $10 \mathrm{kg}$ and $6 \mathrm{kg}$ respectively, are placed on the inclined plane and released, determine the force developed in the link. The coefficients of kinetic friction between the blocks and the inclined plane are $\mu_{A}=0.1$ and $\mu_{B}=0.3 .$ Neglect the mass of the link.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
08:46

Problem 7

The 10 -lb block has a speed of 4 ft $/$ s when the force of $F=\left(8 t^{2}\right)$ Ib is applied. Determine the velocity of the block when it moves $s=30$ ft. The coefficient of kinetic friction at the surface is $\mu_{x}=0.2$

Guilherme Barros
Guilherme Barros
Numerade Educator
03:40

Problem 8

The speed of the 3500 -lb sports car is plotted over the 30 -s time period. Plot the variation of the traction force F needed to cause the motion.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
02:33

Problem 9

The conveyor belt is moving at $4 \mathrm{m} / \mathrm{s}$. If the coefficient of static friction between the conveyor and the 10 -kg package $B$ is $\mu_{s}=0.2,$ determine the shortest time the belt can stop so that the package does not slide on the bclt.

Vishal Gupta
Vishal Gupta
Numerade Educator
03:01

Problem 10

The conveyor belt is designed to transport packages of various weights. Each 10 -kg package has a coefficient of kinetic friction $\mu_{k}=0.15 .$ If the speed of the conveyor is $5 \mathrm{m} / \mathrm{s},$ and then it suddenly stops, determine the distance the package will slide on the belt before coming to rest.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
05:37

Problem 11

Determine the time needed to pull the cord at $B$ down 4 ft starting from rest when a force of 10 lb is applied to the cord. Block $A$ weighs 20 th. Neglect the mass of the pulleys and cords.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
04:25

Problem 12

Cylinder $B$ has a mass $m$ and is hoisted using the cord and pulley system shown. Determine the magnitude of force $\mathbf{F}$ as a function of the block's vertical position $y$ so that when $\mathbf{F}$ is applied the block rises with a constant acceleration a $_{B} .$ Neglect the mass of the cord and pulleys.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
04:44

Problem 13

Block $A$ has a weight of $8 \mathrm{lb}$ and block $B$ has a weight of 6 lb. They rest on a surface for which the coefficient of kinetic friction is $\mu_{k}=0.2 .$ If the spring has a stiffness of $k=20 \mathrm{lb} / \mathrm{ft},$ and it is compressed $0.2 \mathrm{ft}$, determine the acceleration of each block just after they are released.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
05:37

Problem 14

The 2 -Mg truck is traveling at $15 \mathrm{m} / \mathrm{s}$ when the brakes on all its wheels are applied, causing it to skid for a distance of $10 \mathrm{m}$ before coming to rest. Determine the constant horizontal force developed in the coupling $C,$ and the frictional force developed between the tires of the truck and the road during this time. The total mass of the boat and trailer is $1 \mathrm{Mg}$.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
06:18

Problem 15

The motor lifts the 50 -kg crate with an acceleration of $6 \mathrm{m} / \mathrm{s}^{2}$. Determine the components of force reaction and the couple moment at the fixed support $A$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
07:26

Problem 16

The $75-\mathrm{kg}$ man pushes on the 150 -kg crate with a horizontal force $\mathbf{F}$. If the coefficients of static and kinetic friction between the crate and the surface are $\mu_{s}=0.3$ and $\mu_{k}=0.2,$ and the coefficient of static friction between the man's shoes and the surface is $\mu_{x}=0.8,$ show that the man is able to move the crate. What is the greatest acceleration the man can give the crate?

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:23

Problem 17

Determine the acceleration of the blocks when the system is released. The coefficient of kinetic friction is $\mu_{k}$ and the mass of each block is $\mathrm{m}$. Neglect the mass of the pulleys and cord.

Guilherme Barros
Guilherme Barros
Numerade Educator
07:47

Problem 18

A 40 -lb suitcase slides from rest $20 \mathrm{ft}$ down the smooth ramp. Determine the point where it strikes the ground at $C .$ How long does it take to go from $A$ to $C ?$

Sheh Lit Chang
Sheh Lit Chang
University of Washington
07:15

Problem 19

Solve Prob. $13-18$ if the suitcase has an initial velocity down the ramp of $v_{A}=10 \mathrm{ft} / \mathrm{s}$ and the coefficient of kinetic friction along $A B$ is $\mu_{k}=0.2$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
06:41

Problem 20

The conveyor belt delivers each 12 -kg crate to the ramp at $A$ such that the crate's speed is $v_{A}=2.5 \mathrm{m} / \mathrm{s}$ directed down along the ramp. If the coefficient of kinetic friction between each crate and the ramp is $\mu_{k}=0.3$ determine the speed at which each crate slides off the ramp at $B$. Assume that no tipping occurs. Take $\theta=30^{\circ}$.

Guilherme Barros
Guilherme Barros
Numerade Educator
08:05

Problem 21

The conveyor belt delivers each 12 -kg crate to the ramp at $A$ such that the crate's speed is $v_{A}=2.5 \mathrm{m} / \mathrm{s}$ directed down along the ramp. If the coefficient of kinetic friction between each crate and the ramp is $\mu_{k}=0.3$ determine the smallest incline $\theta$ of the ramp so that the crates will slide off and fall into the cart.

Guilherme Barros
Guilherme Barros
Numerade Educator
09:39

Problem 22

The $50-\mathrm{kg}$ block $A$ is released from rest. Determine the velocity of the 15 -kg block $B$ in 2 s.

Guilherme Barros
Guilherme Barros
Numerade Educator
07:42

Problem 23

If the supplied force $F=150 \mathrm{N}$, determine the velocity of the $50-\mathrm{kg}$ block $A$ when it has risen $3 \mathrm{m},$ starting from rest.

Guilherme Barros
Guilherme Barros
Numerade Educator
10:56

Problem 24

A $60-\mathrm{kg}$ suitcase slides from rest $5 \mathrm{m}$ down the smooth ramp. Determine the distance $R$ where it strikes the ground at $B$. How long does it take to go from $A$ to $B ?$

Guilherme Barros
Guilherme Barros
Numerade Educator
10:59

Problem 25

Solve Prob. $13-24$ if the suitcase has an initial velocity down the ramp of $v_{A}=2 \mathrm{m} / \mathrm{s}$, and the coefficient of kinetic friction along $A C$ is $\mu_{k}=0.2$

Guilherme Barros
Guilherme Barros
Numerade Educator
04:04

Problem 26

The $1.5 \mathrm{Mg}$ sports car has a tractive force of $F=4.5 \mathrm{kN} .$ If it produces the velocity described by $v$ - $t$ graph shown, plot the air resistance $R$ versus $t$ for this time period.

Guilherme Barros
Guilherme Barros
Numerade Educator
07:39

Problem 27

The conveyor belt is moving downward at $4 \mathrm{m} / \mathrm{s}$ If the coefficient of static friction between the conveyor and the 15 -kg package $B$ is $\mu_{s}=0.8,$ determine the shortest time the belt can stop so that the package does not slide on the belt.

Guilherme Barros
Guilherme Barros
Numerade Educator
14:20

Problem 28

At the instant shown the 100 -lb block $A$ is moving down the plane at $5 \mathrm{ft} / \mathrm{s}$ while being attached to the 50 -lb block $B$. If the coefficient of kinetic friction between the block and the incline is $\mu_{k}=0.2,$ determine the acceleration of $A$ and the distance $A$ slides before it stops. Neglect the mass of the pulleys and cables.

Guilherme Barros
Guilherme Barros
Numerade Educator
09:27

Problem 29

The force exerted by the motor on the cable is shown in the graph. Determine the velocity of the $200-1 b$ crate when $t=2.5 \mathrm{s}$.

Guilherme Barros
Guilherme Barros
Numerade Educator
08:43

Problem 30

The force of the motor $M$ on the cable is shown in the graph. Determine the velocity of the 400 -kg crate $A$ when $t=2 s$.

Guilherme Barros
Guilherme Barros
Numerade Educator
06:03

Problem 31

The tractor is used to lift the 150 -kg load $B$ with the 24-m-long rope, boom, and pulley system. If the tractor travels to the right at a constant speed of $4 \mathrm{m} / \mathrm{s}$, determine the tension in the rope when $s_{A}=5 \mathrm{m} .$ When $s_{A}=0, s_{B}=0$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
06:18

Problem 32

The tractor is used to lift the 150 -kg load $B$ with the 24 -m-long rope, boom, and pulley system. If the tractor travels to the right with an acceleration of $3 \mathrm{m} / \mathrm{s}^{2}$ and has a velocity of $4 \mathrm{m} / \mathrm{s}$ at the instant $s_{A}=5 \mathrm{m}$, determine the tension in the rope at this instant. When $s_{A}=0, s_{B}=0$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
05:32

Problem 33

Block $A$ and $B$ each have a mass $m .$ Determine the largest horizontal force $\mathbf{P}$ which can be applied to $B$ so that it will not slide on $A$. Also, what is the corresponding acceleration? The coefficient of static friction between $A$ and $B$ is $\mu_{3}$. Neglect any friction between $A$ and the horizontal surface.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
11:56

Problem 34

The $4-\mathrm{kg}$ smooth cylinder is supported by the spring having a stiffness of $k_{A B}=120 \mathrm{N} / \mathrm{m}$. Determine the velocity of the cylinder when it moves downward $s=0.2 \mathrm{m}$ from its equilibrium position, which is caused by the application of the force $F=60 \mathrm{N}$.

Guilherme Barros
Guilherme Barros
Numerade Educator
06:37

Problem 35

The coefficient of static friction between the $200-\mathrm{kg}$ crate and the flat bed of the truck is $\mu_{x}=0.3 .$ Determine the shortest time for the truck to reach a speed of $60 \mathrm{km} / \mathrm{h}$ starting from rest with constant acceleration, so that the crate does not slip.

Guilherme Barros
Guilherme Barros
Numerade Educator
13:55

Problem 36

The $2-1 b$ collar $C$ fits loosely on the smooth shaft. If the spring is unstretched when $s=0$ and the collar is given a velocity of 15 ft $/ \mathrm{s}$, determine the velocity of the collar when $s=1 \mathrm{ft}$.

Guilherme Barros
Guilherme Barros
Numerade Educator
02:16

Problem 37

The 10 -kg block $A$ rests on the 50 -kg plate $B$ in the position shown. Neglecting the mass of the rope and pulley, and using the coefficients of kinetic friction indicated, determine the time needed for block $A$ to slide $0.5 \mathrm{m}$ on the plate when the system is released from rest.

Anand Jangid
Anand Jangid
Numerade Educator
04:12

Problem 38

The 300 -kg bar $B$, originally at rest, is being towed over a series of small rollers, Determine the force in the cable when $t=5 \mathrm{s}$, if the motor $M$ is drawing in the cable for a short time at a rate of $v=\left(0.4 t^{2}\right) \mathrm{m} / \mathrm{s},$ where $t$ is in seconds $(0 \leq t \leq 6 \mathrm{s})$. How far does the bar move in $5 \mathrm{s} ?$ Neglect the mass of the cable, pulley, and the rollers.

Guilherme Barros
Guilherme Barros
Numerade Educator
07:14

Problem 39

An electron of mass $m$ is discharged with an initial horizontal velocity of $\mathbf{v}_{0^{-}}$ If it is subjected to two fields of force for which $F_{x}=F_{0}$ and $F_{y}=0.3 F_{0 .}$ where $F_{0}$ is constant, determine the equation of the path, and the speed of the electron at any time $t$.

Guilherme Barros
Guilherme Barros
Numerade Educator
09:47

Problem 40

The 400 -lb cylinder at $A$ is hoisted using the motor and the pulley system shown. If the speed of point $B$ on the cable is increased at a constant rate from zero to $\mathrm{v}_{B}=10 \mathrm{ft} / \mathrm{s}$ in $t=5 \mathrm{s},$ determine the tension in the cable at $B$ to cause the motion.

Guilherme Barros
Guilherme Barros
Numerade Educator
09:08

Problem 41

Block $A$ has a mass $m_{A}$ and is attached to a spring having a stiffness $k$ and unstretched length $l_{0}$. If another block $B$, having a mass $m_{B}$, is pressed against $A$ so that the spring deforms a distance $d$, determine the distance both blocks slide on the smooth surface before they begin to separate. What is their velocity at this instant?

Guilherme Barros
Guilherme Barros
Numerade Educator
11:02

Problem 42

Block $A$ has a mass $m_{A}$ and is attached to a spring having a stiffiness $k$ and unstretched length $l_{0-}$ If another block $B$, having a mass $m_{B}$, is pressed against $A$ so that the spring deforms a distance $d,$ show that for separation to occur it is necessary that $d>2 \mu_{k} g\left(m_{A}+m_{B}\right) / k,$ where $\mu_{k}$ is the coefficient of kinetic friction between the blocks and the ground. Also, what is the distance the blocks slide on the surface before they separate?

Guilherme Barros
Guilherme Barros
Numerade Educator
11:42

Problem 43

A parachutist having a mass $m$ opens his parachute from an at-rest position at a very high altitude. If the atmospheric drag resistance is $F_{D}=k v^{2}$, where $k$ is a constant, determine his velocity when he has fallen for a time $t .$ What is his velocity when he lands on the ground? This velocity is referred to as the terminal velocity, which is found by letting the time of fall $t \rightarrow \infty$.

Guilherme Barros
Guilherme Barros
Numerade Educator
05:58

Problem 44

If the motor draws in the cable with an acceleration of $3 \mathrm{m} / \mathrm{s}^{2},$ determine the reactions at the supports $A$ and $B$ The beam has a uniform mass of $30 \mathrm{kg} / \mathrm{m},$ and the crate has a mass of $200 \mathrm{kg}$ Neglect the mass of the motor and pulleys.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
09:39

Problem 45

If the force exerted on cable $A B$ by the motor is $F=\left(100 t^{3 / 2}\right) \mathrm{N},$ where $t$ is in seconds, determine the $50-\mathrm{kg}$ crate's velocity when $t=5$ s The coefficients of static and kinetic friction between the crate and the ground are $\mu_{s}=0.4$ and $\mu_{k}=0.3,$ respectively. Initially the crate is at rest.

Guilherme Barros
Guilherme Barros
Numerade Educator
07:28

Problem 46

Blocks $A$ and $B$ each have a mass $m .$ Determine the largest horizontal force $\mathbf{P}$ which can be applied to $B$ so that $A$ will not move relative to $B$. All surfaces are smooth.

Guilherme Barros
Guilherme Barros
Numerade Educator
13:07

Problem 47

Blocks $A$ and $B$ each have a mass $m$. Determine the largest horizontal force $\mathbf{P}$ which can be applied to $B$ so that $A$ will not slip on $B$. The coefficient of static friction between $A$ and $B$ is $\mu_{3}$. Neglect any friction between $B$ and $C$.

Guilherme Barros
Guilherme Barros
Numerade Educator
03:51

Problem 48

The smooth block $B$ of negligible size has a mass $m$ and rests on the horizontal plane. If the board $A C$ pushes on the block at an angle $\theta$ with a constant acceleration a $_{0}$ determine the velocity of the block along the board and the distance $s$ the block moves along the board as a function of time $t .$ The block starts from rest when $s=0, t=0$.

Susan Hallstrom
Susan Hallstrom
Numerade Educator
04:23

Problem 49

If a horizontal force $P=12 \mathrm{lb}$ is applied to block $A$ determine the acceleration of the block $B$. Neglect friction.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
04:15

Problem 50

A freight elevator, including its load, has a mass of 1 Mg. It is prevented from rotating due to the track and wheels mounted along its sides. If the motor $M$ develops a constant tension $T=4 \mathrm{kN}$ in its attached cable, determine the velocity of the elevator when it has moved upward $6 \mathrm{m}$ starting from rest. Neglect the mass of the pulleys and cables.

Guilherme Barros
Guilherme Barros
Numerade Educator
04:15

Problem 51

The block $A$ has a mass $m_{A}$ and rests on the pan $B$, which has a mass $m_{B}$. Both are supported by a spring having a stiffness $k$ that is attached to the bottom of the pan and to the ground. Determine the distance $d$ the pan should be pushed down from the equilibrium position and then released from rest so that separation of the block will take place from the surface of the pan at the instant the spring becomes unstretched.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
04:21

Problem 52

A girl, having a mass of 15 kg, sits motionless relative to the surface of a horizontal platform at a distance of $r=5 \mathrm{m}$ from the platform's center. If the angular motion of the platform is slowly increased so that the girl's tangential component of acceleration can be neglected, determine the maximum speed which the girl will have before she begins to slip off the platform. The coefficient of static friction between the girl and the platform is $\mu=0.2$.

Guilherme Barros
Guilherme Barros
Numerade Educator
03:34

Problem 53

The 2 -kg block $B$ and 15 -kg cylinder $A$ are connected to a light cord that passes through a hole in the center of the smooth table. If the block is given a speed of $v=10 \mathrm{m} / \mathrm{s},$ determine the radius $r$ of the circular path along which it travels.

Guilherme Barros
Guilherme Barros
Numerade Educator
03:48

Problem 54

The 2 -kg block $B$ and 15 -kg cylinder $A$ are connected to a light cord that passes through a hole in the center of the smooth table. If the block travels along a circular path of radius $r=1.5 \mathrm{m},$ determine the speed of the block.

Guilherme Barros
Guilherme Barros
Numerade Educator
04:13

Problem 55

Determine the maximum constant speed at which the pilot can travel around the vertical curve having a radius of curvature $\rho=800 \mathrm{m},$ so that he experiences a maximum acceleration $a_{n}=8 g=78.5 \mathrm{m} / \mathrm{s}^{2} .$ If he has a mass of $70 \mathrm{kg}$ determine the normal force he exerts on the seat of the airplane when the plane is traveling at this speed and is at its lowest point.

Guilherme Barros
Guilherme Barros
Numerade Educator
06:20

Problem 56

Cartons having a mass of 5 kg are required to move along the assembly line at a constant speed of $8 \mathrm{m} / \mathrm{s}$. Determine the smallest radius of curvature, $\rho,$ for the conveyor so the cartons do not slip. The coefficients of static and kinetic friction between a carton and the conveyor are $\mu_{s}=0.7$ and $\mu_{k}=0.5,$ respectively.

Guilherme Barros
Guilherme Barros
Numerade Educator
05:37

Problem 57

The collar $A,$ having a mass of $0.75 \mathrm{kg}$, is attached to a spring having a stiffness of $k=200 \mathrm{N} / \mathrm{m}$. When rod $B C$ rotates about the vertical axis, the collar slides outward along the smooth rod $D E$. If the spring is unstretched when $s=0,$ determine the constant speed of the collar in order that $s=100 \mathrm{mm} .$ Also, what is the normal force of the rod on the collar? Neglect the size of the collar.

Guilherme Barros
Guilherme Barros
Numerade Educator
11:59

Problem 58

The 2 -kg spool $S$ fits loosely on the inclined rod for which the coefficient of static friction is $\mu_{2}=0.2 .$ If the spool is located $0.25 \mathrm{m}$ from $A,$ determine the minimum constant speed the spool can have so that it does not slip down the rod.

Guilherme Barros
Guilherme Barros
Numerade Educator
11:35

Problem 59

The 2 -kg spool $S$ fits loosely on the inclined rod for which the coefficient of static friction is $\mu_{x}=0.2 .$ If the spool is located $0.25 \mathrm{m}$ from $A$, determine the maximum constant speed the spool can have so that it does not slip up the rod.

Guilherme Barros
Guilherme Barros
Numerade Educator
08:00

Problem 60

At the instant $\theta=60^{\circ},$ the boy's center of mass $G$ has a downward speed $v_{G}=15 \mathrm{ft} / \mathrm{s}$. Determine the rate of increase in his speed and the tension in each of the two supporting cords of the swing at this instant. The boy has a weight of 60 lb. Neglect his size and the mass of the seat and cords.

Guilherme Barros
Guilherme Barros
Numerade Educator
09:51

Problem 61

At the instant $\theta=60^{\circ},$ the boy's center of mass $G$ is momentarily at rest. Determine his speed and the tension in each of the two supporting cords of the swing when $\theta=90^{\circ} .$ The boy has a weight of 60 lb, Neglect his size and the mass of the seat and cords.

Guilherme Barros
Guilherme Barros
Numerade Educator
04:47

Problem 62

A girl having a mass of $25 \mathrm{kg}$ sits at the edge of the merry-go-round so her center of mass $G$ is at a distance of $1.5 \mathrm{m}$ from the axis of rotation. If the angular motion of the platform is slowly increased so that the girl's tangential component of acceleration can be neglected, determine the maximum speed which she can have before she begins to slip off the merry-go-round. The coefficient of static friction between the girl and the merry-go-round is $\mu_{2}=0.3$.

Guilherme Barros
Guilherme Barros
Numerade Educator
10:01

Problem 63

The pendulum bob $B$ has a weight of $5 \mathrm{lb}$ and is released from rest in the position shown, $\theta=0^{\circ}$. Determine the tension in string $B C$ just after the bob is released, $\theta=0^{\circ},$ and also at the instant the bob reaches $\theta=45^{\circ}$ Take $r=3 \mathrm{ft}$.

Guilherme Barros
Guilherme Barros
Numerade Educator
06:52

Problem 64

The pendulum bob $B$ has a mass $m$ and is released from rest when $\theta=0^{\circ} .$ Determine the tension in string $B C$ immediately afterwards, and also at the instant the bob reaches the arbitrary position $\theta$.

Guilherme Barros
Guilherme Barros
Numerade Educator
05:06

Problem 65

Determine the constant speed of the passengers on the amusement-park ride if it is observed that the supporting cables are directed at $\theta=30^{\circ}$ from the vertical. Each chair including its passenger has a mass of $80 \mathrm{kg}$. Also, what are the components of force in the $n, t$, and $b$ directions which the chair exerts on a 50 -kg passenger during the motion?

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
02:47

Problem 66

A motorcyclist in a circus rides his motorcycle within the confines of the hollow sphere. If the coefficient of static friction between the wheels of the motorcycle and the sphere is $\mu_{s}=0.4,$ determine the minimum speed at which he must travel if he is to ride along the wall when $\theta=90^{\circ}$ The mass of the motorcycle and rider is $250 \mathrm{kg}$, and the radius of curvature to the center of gravity is $\rho=20 \mathrm{ft}$ Neglect the size of the motorcycle for the calculation.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
05:48

Problem 67

The vehicle is designed to combine the feel of a motorcycle with the comfort and safety of an automobile. If the vehicle is traveling at a constant speed of $80 \mathrm{km} / \mathrm{h}$ along a circular curved road of radius $100 \mathrm{m}$, determine the tilt angle $\theta$ of the vehicle so that only a normal force from the seat acts on the driver. Neglect the size of the driver.

Guilherme Barros
Guilherme Barros
Numerade Educator
11:32

Problem 68

The $0.8-\mathrm{Mg}$ car travels over the hill having the shape of a parabola. If the driver maintains a constant speed of $9 \mathrm{m} / \mathrm{s}$, determine both the resultant normal force and the resultant frictional force that all the wheels of the car exert on the road at the instant it reaches point $A$. Neglect the size of the car.

Guilherme Barros
Guilherme Barros
Numerade Educator
09:48

Problem 69

The $0.8-\mathrm{Mg}$ car travels over the hill having the shape of a parabola. When the car is at point $A$, it is traveling at $9 \mathrm{m} / \mathrm{s}$ and increasing its speed at $3 \mathrm{m} / \mathrm{s}^{2}$. Determine both the resultant normal force and the resultant frictional force
that all the wheels of the car exert on the road at this instant. Neglect the size of the car.

Guilherme Barros
Guilherme Barros
Numerade Educator
06:02

Problem 70

The package has a weight of $5 \mathrm{lb}$ and slides down the chute. When it reaches the curved portion $A B,$ it is traveling at $8 \mathrm{ft} / \mathrm{s}\left(\theta=0^{\circ}\right) .$ If the chute is smooth, determine the speed of the package when it reaches the intermediate point $C\left(\theta=30^{\circ}\right)$ and when it reaches the horizontal plane $\left(\theta=45^{\circ}\right) .$ Also, find the normal force on the package at $C$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
08:23

Problem 71

The 150 -lb man lies against the cushion for which the coefficient of static friction is $\mu_{3}=0.5 .$ Determine the resultant normal and frictional forces the cushion exerts on
him if, it due to rotation about the $z$ axis, he has a constant speed $v=20 \mathrm{ft} / \mathrm{s}$. Neglect the size of the man. Take $\theta=60^{\circ}$.

Guilherme Barros
Guilherme Barros
Numerade Educator
02:59

Problem 72

The 150 -lb man lies against the cushion for which the coefficient of static friction is $\mu_{s}=0.5 .$ If he rotates about the $z$ axis with a constant speed $v=30 \mathrm{ft} / \mathrm{s}$ determine the smallest angle $\theta$ of the cushion at which he will begin to slip off.

Prabhu Ramji
Prabhu Ramji
Numerade Educator
04:55

Problem 73

Determine the maximum speed at which the car with mass $m$ can pass over the top point $A$ of the vertical curved road and still maintain contact with the road. If the car maintains this speed, what is the normal reaction the road exerts on the car when it passes the lowest point $B$ on the road?

Guilherme Barros
Guilherme Barros
Numerade Educator
06:13

Problem 74

Determine the maximum constant speed at which the $2-\mathrm{Mg}$ car can travel over the crest of the hill at $A$ without Ieaving the surface of the road. Neglect the size of the car in the calculation.

Guilherme Barros
Guilherme Barros
Numerade Educator
14:49

Problem 75

The box has a mass $m$ and slides down the smooth chute having the shape of a parabola. If it has an initial velocity of $v_{0}$ at the origin determine its velocity as a function of $x$. Also, what is the normal force on the box, and the tangential acceleration as a function of $x ?$

Guilherme Barros
Guilherme Barros
Numerade Educator
06:39

Problem 76

Prove that if the block is released from rest at point $B$ of a smooth path of arbitrary shape, the speed it attains when it reaches point $A$ is equal to the speed it attains when it falls freely through a distance $h ;$ i.e., $v=\sqrt{2 g h}$.

Guilherme Barros
Guilherme Barros
Numerade Educator
09:06

Problem 77

The cylindrical plug has a weight of 2 lb and it is free to move within the confines of the smooth pipe. The spring has a stiffness $k=14 \mathrm{lb} / \mathrm{ft}$ and when no motion occurs the distance $d=0.5 \mathrm{ft}$. Determine the force of the spring on the plug when the plug is at rest with respect to the pipe. The plug is traveling with a constant speed of $15 \mathrm{ft} / \mathrm{s}$, which is caused by the rotation of the pipe about the vertical axis.

Guilherme Barros
Guilherme Barros
Numerade Educator
03:08

Problem 78

When crossing an intersection, a motorcyclist encounters the slight bump or crown caused by the intersecting road. If the crest of the bump has a radius of curvature $\rho=50 \mathrm{ft},$ determine the maximum constant speed at which he can travel without leaving the surface of the road. Neglect the size of the motorcycle and rider in the calculation. The rider and his motorcycle have a total weight of $450 \mathrm{lb}$.

Guilherme Barros
Guilherme Barros
Numerade Educator
05:01

Problem 79

The airplane, traveling at a constant speed of $50 \mathrm{m} / \mathrm{s}$ is executing a horizontal turn. If the plane is banked at $\theta=15^{\circ},$ when the pilot experiences only a normal force on the seat of the plane, determine the radius of curvature $\rho$ of the turn. Also, what is the normal force of the seat on the pilot if he has a mass of $70 \mathrm{kg}$.

Guilherme Barros
Guilherme Barros
Numerade Educator
09:26

Problem 80

The 2-kg pendulum bob moves in the vertical plane with a velocity of $8 \mathrm{m} / \mathrm{s}$ when $\theta=0^{\circ}$. Determine the initial tension in the cord and also at the instant the bob reaches $\theta=30^{\circ} .$ Neglect the size of the bob.

Guilherme Barros
Guilherme Barros
Numerade Educator
09:01

Problem 81

The 2 -kg pendulum bob moves in the vertical plane with a velocity of $6 \mathrm{m} / \mathrm{s}$ when $\theta=0^{\circ}$. Determine the angle $\theta$ where the tension in the cord becomes zero.

Guilherme Barros
Guilherme Barros
Numerade Educator
10:06

Problem 82

The 8 -kg sack slides down the smooth ramp. If it has a speed of $1.5 \mathrm{m} / \mathrm{s}$ when $y=0.2 \mathrm{m},$ determine the normal reaction the ramp exerts on the sack and the rate of increase in the speed of sack at this instant.

Guilherme Barros
Guilherme Barros
Numerade Educator
04:53

Problem 83

The ball has a mass $m$ and is attached to the cord of length $l$. The cord is tied at the top to a swivel and the ball is given a velocity $\mathbf{v}_{0}$. Show that the angle $\theta$ which the cord makes with the vertical as the ball travels around the circular path must satisfy the equation $\tan \theta \sin \theta=v_{0}^{2} / g l$ Neglect air resistance and the size of the ball.

Guilherme Barros
Guilherme Barros
Numerade Educator
05:56

Problem 84

The 2 -lb block is released from rest at $A$ and slides down along the smooth cylindrical surface. If the attached spring has a stiffness $k=2 \mathrm{lb} / \mathrm{ft}$, determine its unstretched length so that it does not allow the block to leave the surface until $\theta=60^{\circ}$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:49

Problem 85

The spring-held follower $A B$ has a weight of $0.75 \mathrm{lb}$ and moves back and forth as its end rolls on the contoured surface of the cam, where $r=0.2 \mathrm{ft}$ and $z=(0.1 \sin 2 \theta) \mathrm{ft}$ If the cam is rotating at a constant rate of 6 rad/s, determine the force at the end $A$ of the follower when $\theta=45^{\circ} .$ In this position the spring is compressed 0.4 ft. Neglect friction at the bearing $C$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
07:01

Problem 86

Determine the magnitude of the resultant force acting on a 5 -kg particle at the instant $t=2 \mathrm{s}$, if the particle is moving along a horizontal path defined by the equations $r=(2 t+10) \mathrm{m}$ and $\theta=\left(1.5 t^{2}-6 t\right)$ rad, where $t$ is in seconds.

Guilherme Barros
Guilherme Barros
Numerade Educator
07:13

Problem 87

The path of motion of a 5 -lb particle in the horizontal plane is described in terms of polar coordinates as $r=(2 t+1) \mathrm{ft}$ and $\theta=\left(0.5 t^{2}-t\right) \mathrm{rad},$ where $t$ is in seconds, Determine the magnitude of the unbalanced force acting on the particle when $t=2 \mathrm{s}$.

Guilherme Barros
Guilherme Barros
Numerade Educator
05:48

Problem 88

Rod $O A$ rotates counterclockwise with a constant angular velocity of $\dot{\theta}=5 \mathrm{rad} / \mathrm{s}$. The double collar $B$ is pinconnected together such that one collar slides over the rotating rod and the other slides over the horizontal curved rod, of which the shape is described by the equation $r=1.5(2-\cos \theta)$ fi. If both collars weigh 0.75 lb, determine the normal force which the curved rod exerts on one collar at the instant $\theta=120^{\circ} .$ Neglect friction.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
10:16

Problem 89

The boy of mass $40 \mathrm{kg}$ is sliding down the spiral slide at a constant speed such that his position, measured from the top of the chute, has components $r=1.5 \mathrm{m}, \theta=(0.7 t) \mathrm{rad}$ and $z=(-0.5 t) \mathrm{m},$ where $t$ is in seconds Determine the components of force $\mathbf{F}_{r}, \mathbf{F}_{\theta^{\prime}}$ and $\mathbf{F}_{r}$ which the slide exerts on him at the instant $t=2$ s. Neglect the size of the boy.

Guilherme Barros
Guilherme Barros
Numerade Educator
06:33

Problem 90

The 40 -kg boy is sliding down the smooth spiral slide such that $z=-2 \mathrm{m} / \mathrm{s}$ and his speed is $2 \mathrm{m} / \mathrm{s}$. Determine the $r, \theta, z$ components of force the slide exerts on him at this instant. Neglect the size of the boy.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
10:22

Problem 91

Using a forked rod, a $0.5-\mathrm{kg}$ smooth peg $P$ is forced to move along the vertical slotted path $r=(0.5 \theta) \mathrm{m},$ where $\theta$ is in radians. If the angular position of the arm is $\theta=\left(\frac{\pi}{5} r^{2}\right)$ rad, where $t$ is in seconds, determine the force of the rod on the peg and the normal force of the slot on the peg at the instant $t=2 \mathrm{s}$. The peg is in contact with only one edge of the rod and slot at any instant.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
08:52

Problem 92

The arm is rotating at a rate of $\dot{\theta}=4 \mathrm{rad} / \mathrm{s}$ when $\ddot{\theta}=3 \operatorname{rad} / \mathrm{s}^{2}$ and $\theta=180^{\circ}$. Determine the force it must exert on the 0.5 -kg smooth cylinder if it is confined to move along the slotted path. Motion occurs in the horizontal plane.

Keshav Singh
Keshav Singh
Numerade Educator
06:33

Problem 93

If arm $O A$ rotates with a constant clockwise angular velocity of $\dot{\theta}=1.5 \mathrm{rad} / \mathrm{s},$ determine the force arm $O A$ exerts on the smooth 4 -lb cylinder $B$ when $\theta=45^{\circ}$.

Rashmi Sinha
Rashmi Sinha
Numerade Educator
04:54

Problem 94

Determine the normal and frictional driving forces that the partial spiral track exerts on the 200 -kg motorcycle at the instant $\theta=\frac{5}{3} \pi \mathrm{rad}, \quad \dot{\theta}=0.4 \mathrm{rad} / \mathrm{s}, \quad \ddot{\theta}=0.8 \mathrm{rad} / \mathrm{s}^{2}$ Neglect the size of the motorcycle.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
04:20

Problem 95

A smooth can $C$, having a mass of $3 \mathrm{kg}$, is lifted from a feed at $A$ to a ramp at $B$ by a rotating rod. If the rod maintains a constant angular velocity of $\dot{\theta}=0.5 \mathrm{rad} / \mathrm{s}$ determine the force which the rod exerts on the can at the instant $\theta=30^{\circ} .$ Neglect the effects of friction in the calculation and the size of the can so that $r=(1.2 \cos \theta) \mathrm{m}$ The ramp from $A$ to $B$ is circular, having a radius of $600 \mathrm{mm}$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:47

Problem 96

The spring-held follower $A B$ has a mass of $0.5 \mathrm{kg}$ and moves back and forth as its end rolls on the contoured surface of the cam, where $r=0.15 \mathrm{mand} z=(0.02 \cos 2 \theta) \mathrm{m}$ If the cam is rotating at a constant rate of 30 rad/s, determine the force component $F_{z}$ at the end $A$ of the follower when $\theta=30^{\circ} .$ The spring is uncompressed when $\theta=90^{\circ} .$ Neglect friction at the bearing $C$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
04:05

Problem 97

The spring-held follower $A B$ has a mass of $0.5 \mathrm{kg}$ and moves back and forth as its end rolls on the contoured surface of the cam, where $r=0.15 \mathrm{m}$ and $z=(0.02 \cos 2 \theta) \mathrm{m}$ If the cam is rotating at a constant rate of $30 \mathrm{rad} / \mathrm{s}$ determine the maximum and minimum force components $F_{z}$ the follower exerts on the cam if the spring is uncompressed when $\theta=90^{\circ}$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
04:02

Problem 98

The particle has a mass of $0.5 \mathrm{kg}$ and is confined to move along the smooth vertical slot due to the rotation of the arm $O A .$ Determine the force of the rod on the particle and the normal force of the slot on the particle when $\theta=30^{\circ} .$ The rod is rotating with a constant angular velocity $\dot{\theta}=2 \mathrm{rad} / \mathrm{s} .$ Assume the particle contacts only one side of the slot at any instant.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
05:00

Problem 99

A car of a roller coaster travels along a track which for a short distance is defined by a conical spiral, $r=\frac{3}{4} z$ $\theta=-1.5 z,$ where $r$ and $z$ are in meters and $\theta$ in radians. If the angular motion $\dot{\theta}=1 \mathrm{rad} / \mathrm{s}$ is always maintained, determine the $r, \theta, z$ components of reaction exerted on the car by the track at the instant $z=6 \mathrm{m}$. The car and passengers have a total mass of $200 \mathrm{kg}$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
04:14

Problem 100

The $0.5-1 b$ ball is guided along the vertical circular path $r=2 r_{c} \cos \theta$ using the arm $O A$. If the arm has an angular velocity $\dot{\theta}=0.4 \mathrm{rad} / \mathrm{s}$ and an angular acceleration $\ddot{\theta}=0.8 \mathrm{rad} / \mathrm{s}^{2}$ at the instant $\theta=30^{\circ}$
determine the force of the arm on the ball. Neglect friction and the size of the ball. Set $r_{c}=0.4 \mathrm{ft}$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:12

Problem 101

The ball of mass $m$ is guided along the vertical circular path $r=2 r_{c} \cos \theta$ using the arm $O A$. If the arm has a constant angular velocity $\dot{\theta}_{0}$, determine the angle $\theta \leq 45^{\circ}$ at which the ball starts to leave the surface of the semicylinder. Neglect friction and the size of the ball.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
04:25

Problem 102

Using a forked rod, a smooth cylinder $P,$ having a mass of $0.4 \mathrm{kg},$ is forced to move along the vertical slotted path $r=(0.6 \theta) \mathrm{m},$ where $\theta$ is in radians If the cylinder has a constant speed of $v_{c}=2 \mathrm{m} / \mathrm{s}$, determine the force of the rod and the normal force of the slot on the cylinder at the instant $\theta-\pi$ rad. Assume the cylinder is in contact with only one edge of the rod and slot at any instant. Hint: To obtain the time derivatives necessary to compute the cylinder's acceleration components $a_{r}$ and $a_{v}$. take the first and second time derivatives of $r=0.6 \theta$. Then, for further information, use Eq. $12-26$ to determine $\theta$. Also, take the time derivative of Eq. $12-26,$ noting that $\dot{v}=0$ to determine $\ddot{\theta}$.

Andrew C
Andrew C
Numerade Educator
03:30

Problem 103

The pilot of the airplane executes a vertical loop which in part follows the path of a cardioid, $r=200(1+\cos \theta) \mathrm{m},$ where $\theta$ is in radians. If his speed at $A$ is a constant $v_{p}=85 \mathrm{m} / \mathrm{s},$ determine the vertical reaction the seat of the plane exerts on the pilot when the plane is at $A .$ He has a mass of 80 kg. Hint: To determine the time derivatives necessary to calculate the acceleration components $a_{r}$ and $a_{0},$ take the first and second time derivatives of $r=200(1+\cos \theta)$. Then, for further information, use Eq. $12-26$ to determine $\dot{\theta}$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
04:16

Problem 104

The collar has a mass of $2 \mathrm{kg}$ and travels along the smooth horizontal rod defined by the equiangular spiral $r=\left(e^{\theta}\right) \mathrm{m},$ where $\theta$ is in radians. Determine the tangential force $F$ and the normal force $N$ acting on the collar when $\theta=45^{\circ},$ if the force $F$ maintains a constant angular motion $\theta=2 \mathrm{rad} / \mathrm{s}$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:49

Problem 105

The particle has a mass of $0.5 \mathrm{kg}$ and is confined to move along the smooth horizontal slot due to the rotation of the arm $O A .$ Determine the force of the rod on the particle and the normal force of the slot on the particle when $\theta=30^{\circ}$. The rod is rotating with a constant angular velocity $\dot{\theta}=2 \mathrm{rad} / \mathrm{s} .$ Assume the particle contacts only one side of the slot at anv instant.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:56

Problem 106

Solve Prob. $13-105$ if the arm has an angular acceleration of $\ddot{\theta}=3 \operatorname{rad} / \mathrm{s}^{2}$ when $\dot{\theta}=2 \mathrm{rad} / \mathrm{s}$ at $\theta=30^{\circ}$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
10:22

Problem 107

The forked rod is used to move the smooth 2-lb particle around the horizontal path in the shape of a limaçon, $r=(2+\cos \theta)$ ft. If $\theta=\left(0.5 r^{2}\right)$ rad, where $t$ is in seconds, determine the force which the rod exerts on the particle at the instant $t=1$ s. The fork and path contact the particle on only one side.

Sheh Lit Chang
Sheh Lit Chang
University of Washington
05:21

Problem 108

The collar, which has a weight of $3 \mathrm{lb}$, slides along the smooth rod lying in the horizontal plane and having the shape of a parabola $r=4 /(1-\cos \theta),$ where $\theta$ is in radians and $r$ is in feet. If the collar's angular rate is constant and equals $\dot{\theta}=4$ rad/s, determine the tangential retarding force $P$ needed to cause the motion and the normal force that the collar exerts on the rod at the instant $\theta=90^{\circ}$.

Manish Kumar
Manish Kumar
Numerade Educator
05:21

Problem 109

Rod $O A$ rotates counterclockwise at a constant angular rate $\dot{\theta}=4 \mathrm{rad} / \mathrm{s} .$ The double collar $B$ is pinconnected together such that one collar slides over the rotating rod and the other collar slides over the circular rod described by the equation $r=(1.6 \cos \theta) \mathrm{m}$. If both collars have a mass of $0.5 \mathrm{kg}$, determine the force which the circular rod exerts on one of the collars and the force that $O A$ exerts on the other collar at the instant $\theta=45^{\circ} .$ Motion is in the horizontal plane.

Manish Kumar
Manish Kumar
Numerade Educator
03:59

Problem 110

Solve Prob. 13-109 if motion is in the vertical plane.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
07:13

Problem 111

A $0.2-\mathrm{kg}$ spool slides down along a smooth rod. If the rod has a constant angular rate of rotation $\dot{\theta}=2 \mathrm{rad} / \mathrm{s}$ in the vertical plane, show that the equations of motion for the spool are $\ddot{r}-4 r-9.81 \sin \theta=0$ and $0.8 r+N_{x}-1.962 \cos \theta=0,$ where $N_{x}$ is the magnitude of the normal force of the rod on the spool. Using the methods of differential equations, it can be shown that the solution of the first of these equations is $r=C_{1} e^{-2 t}+C_{2} e^{2 t}-(9.81 / 8) \sin 2 t .$ If $r, \dot{r},$ and $\theta$ are zero when $t=0,$ evaluate the constants $C_{1}$ and $C_{2}$ determine $r$ at the instant $\theta=\pi / 4$ rad.

Guilherme Barros
Guilherme Barros
Numerade Educator
03:48

Problem 112

The pilot of an airplane executes a vertical loop which in part follows the path of a "four-leaved rose," $r=(-600 \cos 2 \theta)$ ft, where $\theta$ is in radians. If his speed is a constant $v_{P}=80 \mathrm{ft} / \mathrm{s},$ determine the vertical reaction the seat of the plane exerts on the pilot when the plane is at $A$. He weights 130 lb. Hint: To determine the time derivatives necessary to compute the acceleration components an and $a_{0}$. take the first and second time derivatives of $r=400(1+\cos \theta) .$ Then, for further information, use Eq. $12-26$ to determine
$\theta .$ Also, take the time derivative of Eq. $12-26,$ noting that $\dot{v}_{p}=0$ to determine $\dot{\theta}$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:08

Problem 113

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The earth has an orbit with eccentricity 0.0167 around the sun. Knowing that the earth's minimum distance from the sun is $146\left(10^{6}\right) \mathrm{km},$ find the speed at which the earth travels when it is at this distance. Determine the equation in polar coordinates which describes the earth's orbit about the sun.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
02:38

Problem 114

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
A communications satellite is in a circular orbit above the earth such that it always remains directly over a point on the earth's surface. As a result, the period of the satellite must equal the rotation of the earth, which is approximately 24 hours. Determine the satellite's altitude $h$ above the earth's surface and its orbital speed.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
02:48

Problem 115

The speed of a satellite launched into a circular orbit about the earth is given by Eq. $13-25$. Determine the speed of a satellite launched parallel to the surface of the earth so that it travels in a circular orbit $800 \mathrm{km}$ from the earth's surface.

Guilherme Barros
Guilherme Barros
Numerade Educator
04:27

Problem 116

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The rocket is in circular orbit about the earth at an altitude of $20 \mathrm{Mm}$. Determine the minimum increment in speed it must have in order to escape the earth's gravitational field.

Guilherme Barros
Guilherme Barros
Numerade Educator
01:59

Problem 117

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
Prove Kepler's third law of motion. Hint: Use Eqs. $13-19,13-28,13-29,$ and $13-31$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
02:57

Problem 118

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The satellite is moving in an elliptical orbit with an eccentricity $e=0.25 .$ Determine its speed when it is at its maximum distance $A$ and minimum distance $B$ from the earth.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
01:54

Problem 119

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The rocket is traveling in free flight along the elliptical orbit. The planet has no atmosphere, and its mass is 0.60 times that of the earth. If the rocket has the orbit shown, determine the rocket's speed when it is at $A$ and at $B$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
04:27

Problem 120

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
Determine the constant speed of satellite $S$ so that it circles the earth with an orbit of radius $r=15 \mathrm{Mm}$ Hint: Use Eq. $13-1$.

Guilherme Barros
Guilherme Barros
Numerade Educator
01:48

Problem 121

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The rocket is in free flight along an elliptical trajectory $A^{\prime} A .$ The planet has no atmosphere, and its mass is 0.70 times that of the earth. If the rocket has an apoapsis and periapsis as shown in the figure, determine the speed of the rocket when it is at point $A$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
06:17

Problem 122

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The Viking Explorer approaches the planet Mars on a parabolic trajectory as shown. When it reaches point $A$ its velocity is $10 \mathrm{Mm} / \mathrm{h}$. Determine $r_{0}$ and the required change in velocity at $A$ so that it can then maintain a circular orbit as shown. The mass of Mars is 0.1074 times the mass of the earth.

Guilherme Barros
Guilherme Barros
Numerade Educator
03:52

Problem 123

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The rocket is initially in free-flight circular orbit around the earth. Determine the speed of the rocket at $A$. What change in the speed at $A$ is required so that it can move in an elliptical orbit to reach point $A^{\prime} ?$

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:00

Problem 124

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The rocket is in free-flight circular orbit around the earth. Determine the time needed for the rocket to travel from the innner orbit at $A$ to the outer orbit at $A^{\prime}$

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
01:48

Problem 125

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
A satellite is launched at its apogee with an initial velocity $v_{0}=2500 \mathrm{mi} / \mathrm{h}$ parallel to the surface of the earth. Determine the required altitude (or range of altitudes) above the earth's surface for launching if the free-flight trajectory is to be (a) circular,
(b) parabolic,
(c) elliptical, with launch at apogee, and
(d) hyperbolic. Take
\[
G=34.4\left(10^{-9}\right)\left(\mathrm{lb} \cdot \mathrm{ft}^{2}\right) / \mathrm{slug}^{2}, \quad M_{e}=409\left(10^{21}\right) \mathrm{slug}, \quad \text { the }
\]
earth's radius $r_{c}=3960 \mathrm{mi},$ and $1 \mathrm{mi}=5280 \mathrm{ft}$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
02:23

Problem 126

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The rocket is traveling around the earth in free flight along the elliptical orbit. If the rocket has the orbit shown, determine the speed of the rocket when it is at $A$ and at $B$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:04

Problem 127

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
An elliptical path of a satellite has an eccentricity $e=0.130 .$ If it has a speed of $15 \mathrm{Mm} / \mathrm{h}$ when it is at perigee, $P,$ determine its speed when it arrives at apogee, $A .$ Also, how far is it from the earth's surface when it is at $A ?$

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:52

Problem 128

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
A rocket is in free-flight elliptical orbit around the planet Venus. Knowing that the periapsis and apoapsis of the orbit are $8 \mathrm{Mm}$ and $26 \mathrm{Mm}$, respectively, determine
(a) the speed of the rocket at point $A^{\prime},(b)$ the required speed it must attain at $A$ just after braking so that it undergoes an $8-\mathrm{Mm}$ free-flight circular orbit around Venus, and (c) the periods of both the circular and elliptical orbits. The mass of Venus is 0.816 times the mass of the earth.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
01:49

Problem 129

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The rocket is traveling in a free flight along an elliptical trajectory $A^{\prime} A$. The planet has no atmosphere, and its mass is 0.60 times that of the earth. If the rocket has the orbit shown, determine the rocket's velocity when it is at point $A$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
03:15

Problem 130

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
If the rocket is to land on the surface of the planet, determine the required free-flight speed it must have at $A^{\prime}$ so that the landing occurs at $B$. How long does it take for the rocket to land, going from $A^{\prime}$ to $B ?$ The planet has no atmosphere, and its mass is 0.6 times that of the earth.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
01:58

Problem 131

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The rocket is traveling around the earth in free flight along an elliptical orbit $A C$. If the rocket has the orbit shown, determine the rocket's velocity when it is at point $A$.

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator
01:58

Problem 132

In the following problems, except where otherwise indicated, assume that the radius of the earth is $6378 \mathrm{km}$, the earth's mass is $5.976\left(10^{24}\right) \mathrm{kg}$, the mass of the sun is $1.99\left(10^{30}\right) \mathrm{kg}, \quad$ and $\quad$ the $\quad$ gravitational $\quad$ constant $\quad$ is $G=66.73\left(10^{-12}\right) \mathrm{m}^{3} /\left(\mathrm{kg} \cdot \mathrm{s}^{2}\right)$.
The rocket is traveling around the earth in free flight along the elliptical orbit $A C$. Determine its change in speed when it reaches $A$ so that it travels along the elliptical orbit $A B$

Hariprasad Annamalai
Hariprasad Annamalai
Numerade Educator