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Physics 101 Mechanics
November 2021
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Physics 101 Mechanics Q&A Archive of November 22, 2021

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November 22 of 2021

A drill bit is rotating at 950 revolutions per minute. (a) In units of s?1, its angular speed ???? is: (b) The drill bit takes 6.3 s to reach this angular speed, starting from rest. Its average angular acceleration ???? during this time is:

You attach a cord to the a block of mass m and use it to move the block to the final height h. You can do this either by lifting the block vertically or by sliding it up a frictionless ramp of height h. which of the following statement is true a. the magnitude of the tension in the cord is…

A satellite orbits the earth at constant speed in a perfectly circular orbit (recall that the gravitational force on the satellite always points radically inward toward the center of the earth). when the satellite has moved a short distance along the orbit, which of the following statement is…

A roller coaster is pulled up a hill by a chain attached to a motor the total roller mass is 5000kg. If takes 20second to pull the roller coaster up 50 meter hill, how powerful is the motor? Power=work/time;=work=force*displacement

In a car crash test of original length L hits a concrete wall and comes to a full stop without bouncing back. The wrecked car is now ?L shorter. During collision, the average force applied to the car by the wall is F. Consider the car as system and suppose that yu are stationary with respect…

A basket ball player jumps vertically off the rigid floor. while the play is in contact with the floor a. Neither the floor nor player does work on other b. The floor does non-zero work on the player, by the player does zero work on the floor c. The floor does zero work on the player, by…

The potential energy stored in a spring depends on how much it is stretched. Suppose we have a box attached to the same string, but now the other end of the spring is fastened on the floor. Initially, the box sits on the floor, so that the potential energy of the spring is zero. If the box…

Suppose that a box initially on the shelf at a height h is pushed out of the shelf and allowed to fall to the ground. Taking the box and the earth to be the system, the change in its total energy is a. zero b. the work done by gravity c. the change in its potential energy d. the change in…

uppose that a box initially on the shelf at a height h is pushed out of the shelf and allowed to fall to the ground. Taking the box to be the system, the change in its kinetic energy is a. zero b. mgh c. + 2mgh d. the work done by gravity e. the sum of work done by gravity and the…

A bungee jumper falls from a bridge. Her bungee cord, which has zero mass, applies zero force when not extended and a force proportional to its extension otherwise. Which three of the following statements are true? a. At the fastest point of her fall, her acceleration is zero. b.At the…

A roundabout is rotating and slowing down. Consider the vectors of its angular velocity and angular acceleration. These two vectors are: a. parallel b. It depends whether the roundabout is rotating clockwise or anti-clockwise c. orthogonal d. antiparallel e. No direction is defined,…

Suppose that a box initially on the shelf at a height h is pushed out of the shelf and allowed to fall to the ground. Taking the box to be the system, the change in total energy is a. zero b. the change in its potential energy c. the change in its kinetic energy d. the sum of change…

As you are leaving a building, the door opens outward. If the hinges on the door are on your right, what is the direction of the angular velocity of the door as you open it? a. forwards b. up c. to your left d. down e. to your right

As you are leaving a building, the door opens outward. If the hinges on the door are on your right, what is the direction of the angular velocity of the door as you open it?

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box and the earth to be the system, the change in total energy is numerically equal to a. zero b. the change in its potential energy c. the change in its kinetic energy d. the sum of change in…

An aluminum vat is 15 m long at room temperature (20°C). How much longer is it when it contains boiling water at 1 atm pressure?

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box and the earth to be the system, the change in potential energy is a. mgh b. zero c. - mgh d. equal to the work done by gravity e. equal to the change in the total energy of the box

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box and the earth to be the system, the change in total energy is numerically equal to a. mgh b. the maximum kinetic energy of the box c. zero d. minus the change in its potential energy e.…

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box and the earth to be the system, the external physical forces on the system are a. gravity only b. gravity and your hand c. your hand only d. the acceleration of the box when you lift…

ou lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box to be the system, the box you did to place it on the shelf is a. + mgh b. zero c. -mgh d. 2 mgh e. equal to the change in the total energy of the box

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box to be the system, the change in its total energy is the same as a. the change in its kinetic energy b. The sum of the change in its kinetic and potential energy c. the work done by…

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box to be the system, the value of the change in its total energy is numerically equal to a. mgh b. the maximum kinetic energy of the box c. zero d. the work you did to raise it to a…

Four vectors all have the same magnitude. Vector 1is at 30°Vector 2 is at 110°vector 3 is at 240°and Vector 4 is at 315°Which vector has the greatest magnitude x component and which vector has the least magnitude y component?

The total momentum of a system will change during a collision unless the ____________ force is zero.

A pipe of length 2m is open at both ends. The frequency of a certain harmonic is 410 Hz and the frequency of the next higher harmonic is 492 Hz. Determine the speed of sound in the pipe.

A 72-cm-diameter wheel accelerates uniformly about its center from 60 rpm to 300 rpm in 5.0 seconds. Find the magnitude of the (linear) acceleration of a point on the edge of the wheel 2.0 seconds after it has started accelerating.

An organ pipe is 80.0 cm long and is open at one end and closed at the other (“closed” pipe).The difference in frequency between successive harmonics is equal to 200 Hz. What is the speed of the sound?

If the speed of the end A is 5 m/s then find the speed of end B at the instant when angle is 37°

Plane 1 takes off with a velocity of Va = (295 km/h)i relative to the aircraft carrier. On a 2nd runway which is directed 30 degrees away from the x-axis, plane 2 has a speed of 144 km/h relative to the aircraft carrier What are the x- and y-components of the velocity of plane 1 as…

An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 hours.

if the volume flow rate is Q = 85 L/s,np = 75% Determine the power in of pump.

Calculate the number of molecules in a drop of water weighing 0.05 g.

Calculate the amount of water in grams produced by combustion of 16 g of methane (CH4).

A jogger has to exert a force of 29 N against air resistance to maintain a velocity of 3.6 m/s How do I calculate the rate at which the jogger is expending energy?

A man in a barrel walking competition is moving along smoothly, with his barrel moving forward at 1.0 m/s. a. Think about how the man moves his legs. Is he walking forward or backward? b. From the point of view of the top of the barrel-the man's walking surface-how fast is he walking?

A drill bit is rotating at 950 revolutions per minute. (a) In units of s?1, its angular speed ???? is: (b) The drill bit takes 6.3 s to reach this angular speed, starting from rest. Its average angular acceleration ???? during this time is:

You attach a cord to the a block of mass m and use it to move the block to the final height h. You can do this either by lifting the block vertically or by sliding it up a frictionless ramp of height h. which of the following statement is true a. the magnitude of the tension in the cord is…

A satellite orbits the earth at constant speed in a perfectly circular orbit (recall that the gravitational force on the satellite always points radically inward toward the center of the earth). when the satellite has moved a short distance along the orbit, which of the following statement is…

A roller coaster is pulled up a hill by a chain attached to a motor the total roller mass is 5000kg. If takes 20second to pull the roller coaster up 50 meter hill, how powerful is the motor? Power=work/time;=work=force*displacement

In a car crash test of original length L hits a concrete wall and comes to a full stop without bouncing back. The wrecked car is now ?L shorter. During collision, the average force applied to the car by the wall is F. Consider the car as system and suppose that yu are stationary with respect…

A basket ball player jumps vertically off the rigid floor. while the play is in contact with the floor a. Neither the floor nor player does work on other b. The floor does non-zero work on the player, by the player does zero work on the floor c. The floor does zero work on the player, by…

The potential energy stored in a spring depends on how much it is stretched. Suppose we have a box attached to the same string, but now the other end of the spring is fastened on the floor. Initially, the box sits on the floor, so that the potential energy of the spring is zero. If the box…

Suppose that a box initially on the shelf at a height h is pushed out of the shelf and allowed to fall to the ground. Taking the box and the earth to be the system, the change in its total energy is a. zero b. the work done by gravity c. the change in its potential energy d. the change in…

uppose that a box initially on the shelf at a height h is pushed out of the shelf and allowed to fall to the ground. Taking the box to be the system, the change in its kinetic energy is a. zero b. mgh c. + 2mgh d. the work done by gravity e. the sum of work done by gravity and the…

A bungee jumper falls from a bridge. Her bungee cord, which has zero mass, applies zero force when not extended and a force proportional to its extension otherwise. Which three of the following statements are true? a. At the fastest point of her fall, her acceleration is zero. b.At the…

A roundabout is rotating and slowing down. Consider the vectors of its angular velocity and angular acceleration. These two vectors are: a. parallel b. It depends whether the roundabout is rotating clockwise or anti-clockwise c. orthogonal d. antiparallel e. No direction is defined,…

Suppose that a box initially on the shelf at a height h is pushed out of the shelf and allowed to fall to the ground. Taking the box to be the system, the change in total energy is a. zero b. the change in its potential energy c. the change in its kinetic energy d. the sum of change…

As you are leaving a building, the door opens outward. If the hinges on the door are on your right, what is the direction of the angular velocity of the door as you open it? a. forwards b. up c. to your left d. down e. to your right

As you are leaving a building, the door opens outward. If the hinges on the door are on your right, what is the direction of the angular velocity of the door as you open it?

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box and the earth to be the system, the change in total energy is numerically equal to a. zero b. the change in its potential energy c. the change in its kinetic energy d. the sum of change in…

An aluminum vat is 15 m long at room temperature (20°C). How much longer is it when it contains boiling water at 1 atm pressure?

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box and the earth to be the system, the change in potential energy is a. mgh b. zero c. - mgh d. equal to the work done by gravity e. equal to the change in the total energy of the box

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box and the earth to be the system, the change in total energy is numerically equal to a. mgh b. the maximum kinetic energy of the box c. zero d. minus the change in its potential energy e.…

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box and the earth to be the system, the external physical forces on the system are a. gravity only b. gravity and your hand c. your hand only d. the acceleration of the box when you lift…

ou lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box to be the system, the box you did to place it on the shelf is a. + mgh b. zero c. -mgh d. 2 mgh e. equal to the change in the total energy of the box

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box to be the system, the change in its total energy is the same as a. the change in its kinetic energy b. The sum of the change in its kinetic and potential energy c. the work done by…

You lift a box of mass m from the ground placing it at rest on a shelf at a height h. Taking the box to be the system, the value of the change in its total energy is numerically equal to a. mgh b. the maximum kinetic energy of the box c. zero d. the work you did to raise it to a…

Four vectors all have the same magnitude. Vector 1is at 30°Vector 2 is at 110°vector 3 is at 240°and Vector 4 is at 315°Which vector has the greatest magnitude x component and which vector has the least magnitude y component?

The total momentum of a system will change during a collision unless the ____________ force is zero.

A pipe of length 2m is open at both ends. The frequency of a certain harmonic is 410 Hz and the frequency of the next higher harmonic is 492 Hz. Determine the speed of sound in the pipe.

A 72-cm-diameter wheel accelerates uniformly about its center from 60 rpm to 300 rpm in 5.0 seconds. Find the magnitude of the (linear) acceleration of a point on the edge of the wheel 2.0 seconds after it has started accelerating.

An organ pipe is 80.0 cm long and is open at one end and closed at the other (“closed” pipe).The difference in frequency between successive harmonics is equal to 200 Hz. What is the speed of the sound?

If the speed of the end A is 5 m/s then find the speed of end B at the instant when angle is 37°

Plane 1 takes off with a velocity of Va = (295 km/h)i relative to the aircraft carrier. On a 2nd runway which is directed 30 degrees away from the x-axis, plane 2 has a speed of 144 km/h relative to the aircraft carrier What are the x- and y-components of the velocity of plane 1 as…

An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 hours.

Calculate the number of molecules in a drop of water weighing 0.05 g.

Calculate the amount of water in grams produced by combustion of 16 g of methane (CH4).

A jogger has to exert a force of 29 N against air resistance to maintain a velocity of 3.6 m/s How do I calculate the rate at which the jogger is expending energy?

A man in a barrel walking competition is moving along smoothly, with his barrel moving forward at 1.0 m/s. a. Think about how the man moves his legs. Is he walking forward or backward? b. From the point of view of the top of the barrel-the man's walking surface-how fast is he walking?