Question

A lifter takes 5 s to lift a 20-kg object by 10 m high. (1) What is the work done against gravity? (2) What is the power of the lifter?   

Answer 1

I tried this:

Explanation:

The Work is equal to the change in Gravitational Potential energy:

`W=mgh=20*9.8*10=1960J`

Power is the rate at which Energy/Work is transferred/transformed:

`P=W/t=1960/5=392W`