Question

A 45-kg boy pulls a wagon with a force of 38 N for a distance of 550 m. If the boy

takes 240 s, what is the power expended by the boy?

Answer 1

The whole answer is 87.08 but rounding to 2 number its 87

Step-by-step explanation:

Answer 2

87.08 W

Step-by-step explanation:

Power expended by the boy is power needed/ power experienced to/by the wagon throughout this process of pulling.

When the force F is constant and the angle between the force and the displacement s is θ, then the work done is given by W = Fs cos θ.

Assuming that the force and displacement of the wagon are in the same direction cos(θ)= cos(0)= 1

So, W= 38 * 550 (SI units)

W=20,900 J

`Power = (Work done)/(Time taken)`

Power =
`(20,900)/(240)`

87.08 W