How much Work?

1) How much work does an elevator motor do to lift a 1000 kg elevator a height of 100 m?

Known variables:

mass (m): 1000 kg

height (h): 100m

Work = Force x Distance

We need to find a force. Since there is gravity, all we have to do is multiply it by the mass to get the Force.

1000 x 9.81 = 9810N

w = f x d, so w = 9810 x 100 = 981000 Joules.

$W_{{\rm ext}}$ =9.8×10⁵ J

2) How much power must the motor supply to do this in 50 s at constant speed?

Power = work / time.

P = 981000/50 = 19620 watts.

$P$ =2.0×10⁴ W

Posted

August 12, 2012

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