6. If you hold your arm outstretched with palm upward, as in the figure, the force to keep your arm from falling comes from your deltoid muscle. The arm of a typical person has mass 4.0 kg and the distances and angles shown in the Figure. a. What force must the deltoid muscle provide to keep the arm in this position? b. By what factor does this force exceed the weight of the arm? 15° Deltoid 17 cm 38 cm e201a Person Education, irc

6. If you hold your arm outstretched with palm upward, as in the figure, the force to keep your arm from falling comes from your deltoid muscle. The arm of a typical person has mass 4.0 kg and the distances and angles shown in the Figure. a. What force must the deltoid muscle provide to keep the arm in this position? b. By what factor does this force exceed the weight of the arm? 15° Deltoid 17 cm 38 cm e201a Person Education, irc

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter4: Newton's Laws Of Motion

Section: Chapter Questions

Problem 91AP: The board sandwiched between two other boards in Figure P4.91 weighs 95.5 N. If the coefficient of...

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The Iron Cross When a gymnast weighing 750 N executes the iron cross as in Figure lN.91a, the primary muscles involved in supporting this position are the latissimus dorsi (lats") and the pectoralis major (pecs"). The rings exert an upward force on the aims and support the weight of the gymnast. The force exerted by the shoulder joint on the arm is labeled Fs, while the two muscles exert a total force Fw on the arm. Estimate the magnitude of the force Fw. Note that one ring supports half the weight of the gymnast, which is 375 N as indicated in Figure P8.91b. Assume that the force Fw acts at an angle of 45 below the horizontal at a distance of 4.0 cm from the shoulder joint In your estimate, take the distance from the shoulder joint to the hand to be L = 70 cm and ignore the weight of the arm.
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The board sandwiched between two other boards in Figure P4.91 weighs 95.5 N. If the coefficient of friction between the boards is 0.663, what must be the magnitude of the compression forces (assumed to be horizontal) acting on both sides of the center board to keep it from slipping? Figure P4.91
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