What is the power of the machine?

A machine moves a weight of 500N from the ground to the height of 10m in 5s. The machine has an efficiency of 80%. Calculate the power of the machine.

Anonymous2010-08-21T11:46:49Z

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according to a law of physics

work done = force * displacement
in this case
force = 500 N
displacement = 10 m
therefore work done = 500 * 10
work done = 5000 joules
now according to the formula for power

power = work done / time
therefore power = 5000 joules / 5 sec
= 1000 joules / seconds

but the efficiency of this machine is 80 %
therefore power = 80% of 1000
= 80 /100 * 1000
= 800 joules/ second

Ans) The power of the machine is 800 j/s