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A fully loaded, slow-moving freight elevator has a cab with a total mass of 1250 kg, which is required to travel upward 53 m in 3.1 min, starting and ending at rest. The elevator's counterweight has a mass of only 975 kg, and so the elevator motor must help. What average power is required of the force the motor exerts on the cab via the cable?

User Olaf Hess
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1 Answer

7 votes

Answer:

P= 783.6 W

Step-by-step explanation:

Given that

Total mass M= 1250 Kg

d= 53 m ,in time t= 3.1 min

Counter weight mass ,m = 975 kg

The total net force F

F= M g - m g

F= (1250 - 975 ) x 10 N ( take g =10 m/s²)

F=2750 N

We know that work done by force F

W= F. d

W= 2750 x 53 J

W=145750 J

The power P is the rate of change of work with time .


P=(W)/(t)


P=(145750)/(3.1* 60)\ W

P= 783.6 W

User Milan Gupta
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