Mechanical Advantage The pulley system shown in the figure is used to lift a 52-

Question

Mechanical Advantage The pulley system shown in the figure is used to lift a 52-kgcrate. Note that one chain connects the upper pulley to the ceiling and a second chain connects the lower pulley to the crate. Assume the masses of the chains, pulleys, and ropes are negligible.

Part A

Determine the force F required to lift the crate with constant speed.

Express your answer using two significant figures.

F = _____kN?

Part B

Cupper = _____  kN  ?

Part C

Determine the tension in the lower chain.

Clower = ______  kN  ?

Problem 6.32 Mechanical Advantage The pulley system shown in the figure is used to lift a 52-we crate Note that one chain connects the upper pulley to the ceiling and a second chain connects the lower pulley to the crate Assume the masses of the chains. pulleys, and ropes are negligible Part A Determine the force r required to lift the crate with constant speed.

Explanation / Answer

Since system moves with constant speed acceleration is zero

There are two forces acting on the crate

weight in downward direction and tension due to lower chain in upward direction

w = T1 = mg = 52*9.8= 509.6 N

Which is the answer to part c

Tension in the rope is equal throughout its length so solving forces along lower pullet

T + T = w

T = w/2 = 254.8 N

Which is equal to the force required to lift the crate = F and answer for part a

Now for upper chain solving forces along upper pulley

T2 = T + T = 509.6 N

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