Physics
7th Edition
ISBN: 9780321625915
Author: Douglas C. Giancoli
Publisher: PEARSON
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Chapter 9, Problem 3Q
You can find the center of gravity of a meter stick by resting it horizontally on your two index fingers, and then slowly drawing your fingers together. First the meter stick will slip on one finger, and then on the other, but eventually the fingers meet at the cg.Why does this work?
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You can find the center of gravity of a meter stick by resting it horizontally on your two index fingers, and then slowly drawing your fingers together. First the meter stick will slip on one finger, and then on the other, but eventually the fingers meet at the CG. Why does this work?
A 35 N forearm (we are ignoring the hand for this problem) are held at a 45 deg angle to the vertically oriented humerus. The COM of the forearm is located at a distance of 15 cm from the joint center at the elbow,
and the elbow flexor muscles have a 3 cm moment arm. How much force must be exerted by the elbow flexor muscles to maintain this position?
Hide answer choices A
A 35 N
C
81.7 N
123.7 N
D 371 N
Fm
45°
*
--Wt₂
A 50 N hand and forearm are held at a 35° angle to the vertically oriented humerus. The CG of the forearm and hand is located at a distance of 12.5 cm from the joint center at the elbow, and the elbow flexor muscles attach at an average distance of 2.5 cm from the joint center. (Assume that the muscles attach at an angle of 35° to the forearm bones.) How much force must be exerted by the forearm flexors to maintain this position?
Chapter 9 Solutions
Physics
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