Question

If you pick a mass of 11.4 kg from the ground up to 0.84 m above the ground and it takes 2.3 s to do so, how much power is expended?

Answer 1

Power is the rate at which energy is transferred with respect to time.

When you pick a mass m from the ground up to a height h, that mass gains potential energy (U), which is given by:

`U=mgh`

Where g is the gravitational acceleration:

`g=9.81(m)/(s^2)`

Find the potential energy that the mass of 11.4kg gains when it is raised 0.84m:

Then, divide the total potential energy by 2.3s to find the power expended in doing so:

`P=(U)/(t)=(93.94056J)/(2.3s)=40.84372174\ldots W\approx41W`

Therefore, the power expended to raise a mass of 11.4kg up to 0.84m above the ground in 2.3 seconds, is 41 Watts.