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In the figure below, two blocks, of mass m 1 = 360 g and m 2 = 750 g, are connec

ID: 2138260 • Letter: I

Question

In the figure below, two blocks, of mass m1 = 360 g and m2 = 750 g, are connected by a massless cord that is wrapped around a uniform disk of mass M = 500 g and radius R = 12.0 cm. The disk can rotate without friction about a fixed horizontal axis through its center; the cord cannot slip on the disk. The system is released from rest.  

In the figure below, two blocks, of mass m1 = 360 g and m2 = 750 g, are connected by a massless cord that is wrapped around a uniform disk of mass M = 500 g and radius R = 12.0 cm. The disk can rotate without friction about a fixed horizontal axis through its center; the cord cannot slip on the disk. The system is released from rest. Find the magnitude of the acceleration of the blocks. Find the tension T1 in the cord at the left. Find the tension T2 in the cord at the right.

Explanation / Answer

for block 1
T1 - m1g = m1a

for block 2

m2g - T2 = m2a

for pully

RT2 - RT2 = 1/2 M R^2 alpha

T2 - T1 = 1/2 M a

add equations

m2g - m1g = m1a + m2a + 1/2 M a

(.75-.36)*9.81 = (.36+.75+0.5*.5)*a

a=2.81

b)
T1 = .36*(9.81+2.81)=4.54

c) T2 = m2g - m2a = .75*(9.81-2.81)=5.25