Question

An object with a mass of `2 kg` is moving at `5 m/s` over a surface with a kinetic friction coefficient of `3`. How much power will it take to accelerate the object at #3 m/s^2?

Answer 1

The power is `=324W`

Explanation:

The frictional force is

`F_r=mu_k*N`

The normal force is `N=mg`

So,

`F_r=mu_k*mg`

Resolving in the horizontal direction `rarr^+`

We apply Newton's second Law

`F-F_r=ma`

So,

`F=F_r+ma`

`F=mu_kmg+ma`

`=m(mu_kg+a)`

`=2(3*9.8+3)`

`=2*32.4=64.8N`

The power needed is

`P=F*v=64.8*5=324W`