At the instant shown, point P on the cable has a velocity 12 m/s, which is
increasing at the rate of 6m/s^2. Determine the power input of motor M at this
instant if it operates with an efficiency of 0.8. The mass of the block A is 50kg. I've attached a picture of the problem.
Power = F*v (F=force, v=velocity)
The Attempt at a Solution
All I did was make an attempt at drawing free-body diagrams. For the block A of 50kg, I did:
2T-mg=ma; 2T-50(g)=50(6); T= 395 N
Then for point P, I assumed 395 = force of the motor, and thus:
Input Power = (4,740/.8) = 5,925 W
This is wrong obviously, and was hoping if someone could help me out on where I'm going wrong.
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