# A person exerts a power of 175W in lifting a 102.0 kg object vertically at a distance of 2.5 m in a time of 2.3 s.?

What is the percent efficiency of the lift?

### 2 Answers

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- oldschoolLv 76 months ago
Work done = mgh = 102kg * 9.8m/s² *2.5m = 2499J

2499J/2.3s = 1087J/s = 1087W

WRONG DATA

Check your numbers. Is that 102N?

102N*2.5m/2.3s = 111W

111/175 = 63.4%

Maybe that is 10.2kg

mgh = 10.2*9.8*2.5 = 249.9J

249.9J/2.3s =108.7W

108.7/175 = 62.0%

- Anonymous6 months ago
power = mass * g * height / time

efficiency = power from above / 175 W * 100

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