Log out Go to App
Go to App

Learning Materials

Features

Discover

Chapter 9: Q 31E (page 318)

We analyzed the biceps muscle example with the angle between forearm and upper arm set at 90o. Using the same numbers as inExample 9.4, find the force exerted by the biceps muscle when the angle is 120oand the forearm is in a downward position.

Short Answer

Expert verified

The force exerted by the biceps muscle is 407N.

Step by step solution

01

Given Data

The diagram for the biceps muscle is shown below:

02

Calculation of the force

The free body diagram is shown below:

As the force applied by the biceps muscle is perpendicular to the forearm, applying the condition of equilibrium under torque, we can write,

FBr1=War2+Wbr3cos30°FB=War2r1+Wbr3r1cos30°=2.5×9.8×164.0+4×9.8×384.0cos30°=407N

Thus, the force exerted by the biceps muscle is 407 N.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

To get up on the roof, a person (mass \(70.0\;{\rm{kg}}\)) places a \(6.00\;{\rm{m}}\)aluminum ladder (mass \(10.0\;{\rm{kg}}\)) against the house on a concrete pad with the base of the ladder \(2.00\;{\rm{m}}\)from the house. The ladder rests against a plastic rain gutter, which we can assume to be frictionless. The center of mass of the ladder is \(2\;{\rm{m}}\)from the bottom. The person is standing \(3\;{\rm{m}}\) from the bottom. What are the magnitudes of the forces on the ladder at the top and bottom?

When opening a door, you push on it perpendicularly with a force of 55.0 N at a distance of 0.850 m from the hinges. What torque are you exerting relative to the hinges? (b) Does it matter if you push at the same height as the hinges?

Consider a method for measuring the mass of a person’s arm in anatomical studies. The subject lies on her back, extends her relaxed arm to the side and two scales are placed below the arm. One is placed under the elbow and the other under the back of her hand. Construct a problem in which you calculate the mass of the arm and find its center of mass based on the scale readings and the distances of the scales from the shoulder joint. You must include a free body diagram of the arm to direct the analysis. Consider changing the position of the scale under the hand to provide more information, if needed. You may wish to consult references to obtain reasonable mass values.

A typical car has an axle with \({\rm{1}}{\rm{.10}}\;{\rm{cm}}\) radius driving a tire with a radius of \({\rm{27}}{\rm{.5}}\;{\rm{cm}}\). What is its mechanical advantage assuming the very simplified model inFigure\({\rm{9}}{\rm{.25}}\)(b)?

What force does the nail puller inExercise\({\rm{9}}{\rm{.19}}\)exert on the supporting surface? The nail puller has a mass of\({\rm{2}}{\rm{.10}}\;{\rm{kg}}\).
See all solutions

Recommended explanations on Physics Textbooks

Magnetism

Read Explanation

Magnetism and Electromagnetic Induction

Read Explanation

Conservation of Energy and Momentum

Read Explanation

Famous Physicists

Read Explanation

Further Mechanics and Thermal Physics

Read Explanation

Astrophysics

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.

Sign-up for free