(Physics Question): A motor having a maximum power rating of 8.1 x 10^4 watts is used to operate an elevator. What is the maximum weight….?

What is the maximum weight this motor can lift at an average speed of 3 m/s? (show work on how to get answer)

Answer 1

Power = Work ÷ time
Work = Force * distance
Power = Force * distance ÷ time
Power = Weight * Velocity

Since the elevator is moving upward at a average speed, this equation can be used to determine the maximum weight this motor can lift.

8.1 * 10^4 = Weight * 3
Weight = 8.1 * 10^4 ÷ 3 = 2.7 * 10^4 N

Answer 2

The motor can produce F = P/v = 8.1E4/3 = 2.7E4 Newtons of lifting force. But there will be friction and losses, so the max weight the lift can lift will be something less than that value. ANS.

Answer 3

Power = change in energy / time

The energy changing is PE, m*g*h
Power = m*g*h/t

Separate
Power = (m*g)*(h/t)

Define as follows
M*g = weight
H/t = vertical speed

Sub in and solve for weight
Power = weight*v
Weight = power/v = 81000 W / 3 m/s = 27000 N

Presto!

Answer 4

P=W/t = Fv
81000W=F(3)
81000/3= F
F=27000N or 2.7 × 10^4N
Since elevator in included in max weight, this is the answer.

Answer 5

assuming 100% efficiency
m = (p * e) / (g * v)
m = (81000 * 1) / (9.81 * 3)
m = 2752.29 kg <===ans

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