Download the App!

Get 24/7 study help with the Numerade app for iOS and Android! Enter your email for an invite.

Get the answer to your homework problem.

Try Numerade free for 7 days

Like

Report

Downward-Facing Dog. One yoga exercise, known as the "Downward-Facing Dog," requires stretching your hands straight out above your head and bending down to lean against the floor. This exercise is performed by a certain 750 $\mathrm{N}$ person, as shown in the simplified model in Figure $10.83 .$ When he bends his body at the hip to a $90^{\circ}$ angle between his legs and trunk, his legs, trunk, head and arms have the dimensions indicated. Furthermore, his legs and feet weigh a total of 277 $\mathrm{N}$ , and their center of mass is 41 $\mathrm{cm}$ from his hip, measured along the upper body. (a) Find the normal force that the floor exerts on each foot and on each hand, assuming that the person does not favor either hand or either foot. (b) Find the friction force on each foot and on each hand, assuming that it is the same on both feet and on both hands (but not necessarily the same on the feet as on the hands). [Hint: First treat his entire body as a system; then isolate his legs (or his upper body).]

a) foot is ${200 \mathrm{N}}$hand is $\frac{N_{2}}{2}=175 \mathrm{N}$b) foot 92$N$hand is also $92 \mathrm{N}$

Physics 101 Mechanics

Chapter 10

Dynamics of Rotational Motion

Newton's Laws of Motion

Rotation of Rigid Bodies

Equilibrium and Elasticity

Cornell University

University of Michigan - Ann Arbor

Simon Fraser University

Hope College

Lectures

02:34

In physics, a rigid body i…

02:21

In physics, rotational dyn…

08:04

The yoga exercise "Do…

08:13

BIO Downward-Facing Dog. O…

01:50

Assume a person bends forw…

0:00

A person bending forward t…

03:57

02:13

You take your dog Clea to …

02:33

01:33

02:52

05:32

$\bullet$ The forces on th…

05:19

A person is walking three…

04:20

. Leg raises. In a simpli-…

21:48

One day when your friend f…

05:24

In the human arm, the fore…

06:05

In a simplified version of…

02:59

$\bullet$ Friction at the …

03:44

Forearm. In the human arm,…

05:12

Two dogs pull horizontally…

03:01

05:43

As part of an exercise pro…

so he should first draw a couple diagrams. Just Teo really know exactly what's going on. So we essentially have triangle like this at this end. Right here. This is your hands. And this end, right here is your feet. So we can say that this length right here is 90 centimeters. Um, this is a right angle. Ah, this angry here can be measured data, and this will be labeled Fi. We're going to say that this is except one. This is except two. And that this length right here is 135 centimeters. And we know that Ah, this entire length is equaling 162 centimeters. So let's defined this further. We have the force of friction for your feet. The force normal of your feet, The weight of your feet, every one of your legs. Essentially, this right here is 49 centimeters. This right here is 41 centimeters, and this right here is again Fada, right here is Thie force of friction for your hands right here. Is the force normal for your hands? Right? Here's again, Fi. This would be the weights of teeth. So essentially the weight of your arms, and this will be 65 centimeters, and this would be 70 70 years. So this is essentially modeling the yoga's yoga position, and we will take this side And hey, the new diagram going up again, the force normal of your feet to the right force. Friction of your feet. This is again Seita. Going straight down would be the weights of one. This is the weight of your, um, legs. And here again, we have 49 centimetres here. 41 centimeters here and then going perpendicular to this bar or to your legs is the force. And this is your access. So once we have all of these, these air this is the full three free body diagrams we went from kind of vague to more specific. Teo. Even more specific, Um, this is essential if you want to know exactly what's going on. So four party, they want us to find the force normal for each hand so we can say that the net torque it's going to be equal to zero, and this will be equal to the forced normal on both hands times 162 centimeters minus the weight sub one times 27 0.2 centimeters and then minus weights of tea of 103.8 centimeters. No force normal of the hand you simply need to solve. And this will be 27.2 times 22 177 plus 103.8 times 473. And then this will be divided by 162. And this is equaling 350 Nunes. So force normal will equal 175 Newtons for each hand. So this would be your answer for party? Um, your first answer for party. The second part of the question wants us to find the force normal for each foot. So we can say that the signal path in the white direction is again zero. This will equal the force normal of feet, plus the force normal of your hands minus the weight of your legs minus the weight of your arms. And so force normal of your foot of your feet are going to be able to the weights of one. Let's wait some too minus and of age. This will be equal to 277 plus 473 minus 350. This is giving us 400 Nunes so essentially forced normal equal to 100. Nunes. However, this will be for it foot. So this severe second and final answer for apart, eh? We're part B. Now they want us to find the friction force. So we can say that Sigma Tau equals zero and this will equal the force of friction of your foot. This will be equal to 74.9 centimeters plus the weights of one times 22.8 centimeters minus the force normal of the foot times 50 centimetres. Now, at this point, we know that the sum of forces in the axe direction will equal zero. And this will equal force of friction for your foot. And this equals force, brother, minus force of friction for your hand. Therefore, the force of friction for your foot equals the force of friction for your hand. So that's convenient. We can say that the force of friction for your hand, which equals the force of friction for your foot, will equal. You simply have to solve this out. So it'll be 400 Newton's times 50 centimetres minus 277 times 22 0.8 and this will be divided by again 74.9. And this is giving us 183 Newtons. Which means that Ah frictional force Force of friction Well equal 91.5 Nunes four and each foot. This is your final answer for part B. That is the end of the solution. Thank you for watching.

View More Answers From This Book

Find Another Textbook

In physics, a rigid body is an object that is not deformed by the stress of …

In physics, rotational dynamics is the study of the kinematics and kinetics …

The yoga exercise "Downward-Facing Dog" requires stretching your h…

BIO Downward-Facing Dog. One yoga exercise, known as the "Downward-Faci…

Assume a person bends forward to lift a load "with his back" as sh…

A person bending forward to lift a load “with his back” (Fig. P 8.23a) rathe…

A person bending forward to lift a load “with his back” (Fig. P12.51a) rathe…

You take your dog Clea to the vet, and the doctor decides he must locate the…

Assume a person bends forward to lift a load “with his back” as shown in Fig…

$\bullet$ The forces on the foot. $A 750 \mathrm{N}$ athlete standing on one…

A person is walking three dogs fastened to separate leashes that meet in a …

. Leg raises. In a simpli- fied version of the musculature action in leg rai…

One day when your friend from Problem 40 is picking up a package, you notice…

In the human arm, the forearm and hand pivot about the elbow joint. Consider…

In a simplified version of the musculature action in leg raises, the abdomin…

$\bullet$ Friction at the hip joint. Fig-ure 5.51 shows the bone structu…

Forearm. In the human arm, the forearm and hand pivot about the elbow joint.…

Two dogs pull horizontally on ropes attached to a post; the angle between th…

As part of an exercise program, a 75-kg person does toe raises in which he r…

03:10

Measuring $g .$ One way to measure $g$ on another planet or moon by remote s…

04:58

Each of three resistors in Figure 19.68 has a resistance of 2.00$\Omega$ and…

06:24

$\bullet$ A steel wire 2.00 $\mathrm{m}$ long with circular cross section mu…

12:58

If an ohmmeter is connected between points $a$ and $b$ in each of the circui…

02:15

Moving source vs. moving listener. (a) A sound source producing 1.00 kHz…

02:56

$\cdot$ Inside the earth and the sun. (a) Geophysicists have esti- mated tha…

07:14

(a) A set of point charges is held in place at the vertices of an equilatera…

02:26

$$ \begin{array}{l}{\text { (II) A light-year is the distance light travels …

02:48

A gun shoots a shell into the air with an initial velocity of $100.0 \mathrm…

03:37

$\bullet$ $\bullet$ $\bullet$ Mass extinctions. One of the greatest mass ext…