Question

An object with a mass of `12 kg` is on a surface with a kinetic friction coefficient of `15`. How much force is necessary to accelerate the object horizontally at `4 m/s^2`?

Answer 1

The force is `=1812N`

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)`

`=12(15*9.8+4)`

`=12*151=1812N`