EBK UNDERSTANDING OUR UNIVERSE (THIRD E
3rd Edition
ISBN: 9780393631760
Author: Blumenthal
Publisher: VST
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Chapter 14, Problem 31QAP
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Reason behind the usage of X-ray, infrared and radio observations to probe the centre of our galaxy.
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During a concentric loading of the quadriceps muscle in the upper leg, an athlete extends his lower leg from a vertical position (see figure (a)) to a fully extended horizontal position (see figure (b)) at a constant angular speed of 45.0° per second. Two of the four quadriceps muscles, the
vastis intermedius and the rectus femoris, terminate at the patellar tendon which is attached to the top of the tibia in the lower leg. The distance from the point of attachment of the patellar tendon to the rotation axis of the tibia relative to the femur is 4.10 cm in this athlete.
a
b
(a) The two quadriceps muscles can exert a maximum force of 225 N through the patellar tendon. This force is applied at an angle of 25.0° to the section of the tibia between the attachment point and the rotation axis. What is the torque (in N⚫ m) exerted by the muscle on the lower leg
during this motion? (Enter the magnitude.)
N⚫ m
(b) What is the power (in W) generated by the athlete during the motion?
W
(c)…
=
A hanging weight, with a mass of m₁ = 0.365 kg, is attached by a rope to a block with mass m₂ 0.835 kg as shown in the figure below. The rope goes over a pulley with a mass of M = 0.350 kg. The pulley can be modeled as a hollow cylinder with an inner radius of R₁ = 0.0200 m, and
an outer radius of R2 = 0.0300 m; the mass of the spokes is negligible. As the weight falls, the block slides on the table, and the coefficient of kinetic friction between the block and the table is μk = 0.250. At the instant shown, the block is moving with a velocity of v; = 0.820 m/s toward
the pulley. Assume that the pulley is free to spin without friction, that the rope does not stretch and does not slip on the pulley, and that the mass of the rope is negligible.
mq
R₂ R₁
mi
(a) Using energy methods, find the speed of the block (in m/s) after it has moved a distance of 0.700 m away from the initial position shown.
m/s
(b) What is the angular speed of the pulley (in rad/s) after the block has moved this…
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Chapter 14 Solutions
EBK UNDERSTANDING OUR UNIVERSE (THIRD E
Ch. 14.1 - Prob. 14.1CYUCh. 14.2 - Prob. 14.2CYUCh. 14.3 - Prob. 14.3CYUCh. 14.4 - Prob. 14.4CYUCh. 14 - Prob. 1QAPCh. 14 - Prob. 2QAPCh. 14 - Prob. 3QAPCh. 14 - Prob. 4QAPCh. 14 - Prob. 5QAPCh. 14 - Prob. 6QAP
Ch. 14 - Prob. 7QAPCh. 14 - Prob. 8QAPCh. 14 - Prob. 9QAPCh. 14 - Prob. 10QAPCh. 14 - Prob. 11QAPCh. 14 - Prob. 12QAPCh. 14 - Prob. 13QAPCh. 14 - Prob. 14QAPCh. 14 - Prob. 15QAPCh. 14 - Prob. 16QAPCh. 14 - Prob. 17QAPCh. 14 - Prob. 18QAPCh. 14 - Prob. 19QAPCh. 14 - Prob. 20QAPCh. 14 - Prob. 21QAPCh. 14 - Prob. 22QAPCh. 14 - Prob. 23QAPCh. 14 - Prob. 24QAPCh. 14 - Prob. 25QAPCh. 14 - Prob. 27QAPCh. 14 - Prob. 28QAPCh. 14 - Prob. 29QAPCh. 14 - Prob. 30QAPCh. 14 - Prob. 31QAPCh. 14 - Prob. 32QAPCh. 14 - Prob. 33QAPCh. 14 - Prob. 34QAPCh. 14 - Prob. 35QAPCh. 14 - Prob. 36QAPCh. 14 - Prob. 37QAPCh. 14 - Prob. 38QAPCh. 14 - Prob. 39QAPCh. 14 - Prob. 40QAPCh. 14 - Prob. 41QAPCh. 14 - Prob. 43QAPCh. 14 - Prob. 44QAPCh. 14 - Prob. 45QAP
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