Problem 8.58 Part A Two masses, mA 32.0 kg and m 42.0 kg are connected by a rope
ID: 1774717 • Letter: P
Question
Problem 8.58 Part A Two masses, mA 32.0 kg and m 42.0 kg are connected by a rope that hangs over a pulley (as in the figure(Figure 1)). The pulley is a uniform cylinder of radius R = 0.319 m and mass 3.2 kg . Initially, mA is on the ground and mB rests 2.5 m above the ground If the system is now released, use conservation of energy to determine the speed of mp just before it strikes the ground. Assume the pulley is frictionless Express your answer using three significant figures and include the appropriate units u= 1 Value Units Figure 1 of 1 Submit My Answers Give Up Incorrect Try Again; 8 attempts remaining Provide Feedback Continue 11m 11n 2.5 mExplanation / Answer
Applying energy conservation,
PEi + KEi = PEf + KEf
(mB g h ) + 0 = (mA g h) + (mA v^2 /2 + mB v^2 /2 + I w^2 / 2)
2 g h (mB - mA) = v^2 (mA + mB) + (M R^2 /2 )(v/R)^2
2 g h (mB - mA) = v^2 ( mA + mB + M/2)
2 x 9.81 x 2.5 (42 - 32) = v^2 (42 + 32 + 3.2/2)
v = 2.55 m/s ........Ans