Physics_Forces (?)

Practice Question Solving
1

I thoughts this would equale F=MA? To create a system in equilibrium where the piano sits.

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A man lifts at constant velocity a piano weighing 100 kg using a pulley system as shown in the figure.

Question 54 (Cod. : Simu2953_e)
Subject: PHYSICS
Ignoring friction and assuming g = 10 m/s2, what force does the man exert to pull the rope?
A: 100 N
B: 200 N
C: 500 N
D: 750 N
E: 1000 N

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2

Hi!

This video helped me solve this question: Khan Academy
Say the person is pulling down 2 m of rope, then the piano goes up 1m
Wout = Fd = mgd = 100 * 10 * 1 = 1000 J
Win=Wout
so: Win = 1000 J
F * 2 = 1000
F = 1000/2 = 500 N

Hope this helps!

3

I see, the pulley equated to half the work done.
I am gonna owe you after all this Juliette haha,

1 Like
4

No worries! these questions really help me revise