Question

Jill pulls on a rope to lift a 12 kg pail out of a well, while the clumsy Jack watches. For a 10.0 meter segment of the lift, she lifts the bucket straight up at constant speed. How much power is required to complete this task in 5.0 seconds?

Answer 1

Definition of power is the amount of work done per unit of time:

`P=(W)/(t)`
We need to calculate the work done by Jill.
Work is defined as the force acting along the path:

`W=F\cdot h`
In this case, Jill is working against the force of gravity along the path of 10 meters:

`W=mgh=12\cdot9.81\cdot 10=1177.2 J`
Now we can calculate the power:

`P=(1177.2)/(5)= 235.44 W`