College Physics
1st Edition
ISBN: 9781938168000
Author: Paul Peter Urone, Roger Hinrichs
Publisher: OpenStax College
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Chapter 9, Problem 33PE
A 75-kg man stands on his toes by exerting an upward force through the Achilles tendon, as in Figure 9.42. (a) What is the force in the Achilles tendon if he stands on one foot? (b) Calculate the force at the pivot of the simplified lever system shown—that force is representative of forces in the ankle joint.
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Chapter 9 Solutions
College Physics
Ch. 9 - What can you say about the velocity of a moving...Ch. 9 - Under what conditions can a rotating body be in...Ch. 9 - What three factors affect the torque created by a...Ch. 9 - A wrecking ball is being used to knock down a...Ch. 9 - Mechanics put a length of Pipe over the handle of...Ch. 9 - A round pencil lying on its side as in Figure 9.13...Ch. 9 - Explain the need for tall towers on a suspension...Ch. 9 - When visiting some countries, you may see a person...Ch. 9 - Scissors are like a double-lever "Stem, Which of...Ch. 9 - Suppose you pull a nail at a constant rate using a...
Ch. 9 - Why are the forces exerted on the outside world by...Ch. 9 - Explain why the forces in our joints are several...Ch. 9 - Why are the forces exerted on the outside world by...Ch. 9 - Explain why the forces in our joints are several...Ch. 9 - Certain of dinosaurs were bipedal (walked on two...Ch. 9 - Swimmers and athletes during competition need to...Ch. 9 - If the maximum force the biceps muscle can exert...Ch. 9 - Suppose the biceps muscle was attached through...Ch. 9 - Explain one of the reasons why pregnant women...Ch. 9 - (a) When opening a door, you push on it...Ch. 9 - When tightening a bolt, you push perpendicularly...Ch. 9 - Two children push on opposite sides of a door...Ch. 9 - Use the second condition for equilibrium (net =0 )...Ch. 9 - Repeat the seesaw problem in Example 9.1 with the...Ch. 9 - Suppose a horse leans against a wall as in Figure...Ch. 9 - Two children of mass 20.0 kg and 30.0 kg sit...Ch. 9 - (a) Calculate the magnitude and direction of the...Ch. 9 - A person carries a plank of wood 2.00 m long with...Ch. 9 - A 17.0-m-high and 11.0-m-long wall under...Ch. 9 - (a) What force must be exerted by the wind to...Ch. 9 - Suppose the weight of the drawbridge in Figure...Ch. 9 - Suppose a 900-kg car is on the bridge in Figure...Ch. 9 - A sandwich board advertising sign is constructed...Ch. 9 - (a) What minimum coefficient of friction is needed...Ch. 9 - A gymnast is attempting to perform splits. From...Ch. 9 - To get up on the roof, a person (mass 70.0 kg)...Ch. 9 - In Figure 9.21, the cg of the pole held by the...Ch. 9 - What is the mechanical advantage of a nail puller...Ch. 9 - Suppose you needed to raise a 250-kg mower a...Ch. 9 - a) What is the mechanical advantage of a...Ch. 9 - A typical car has an axle with 1.10 cm radius...Ch. 9 - What force does the nail puller in Exercise 9.19...Ch. 9 - If you used an ideal pulley of the type shown in...Ch. 9 - Repeat Exercise 9.24 for the pulley shown in...Ch. 9 - Verity that the force in the elbow joint in...Ch. 9 - Two muscles in the back of the leg pull on the...Ch. 9 - The upper leg muscle (quadriceps) exerts a force...Ch. 9 - A device for exercising the upper leg muscle is...Ch. 9 - A person working at a drafting board may hold her...Ch. 9 - We analyzed the biceps muscle example with the...Ch. 9 - Even when the head is held erect, as in Figure...Ch. 9 - A 75-kg man stands on his toes by exerting an...Ch. 9 - A father lifts his child as shown in Figure 9.43....Ch. 9 - Unlike most of the other muscles in our bodies,...Ch. 9 - Integrated Concepts Suppose we replace the 4.0-kg...Ch. 9 - (a) What force should the woman in Figure 9.45...Ch. 9 - You have just planted a sturdy 2-m-tall palm tree...Ch. 9 - Unreasonable Results Suppose two children are...Ch. 9 - Construct Your Own Problem Consider a method for...
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