Question

An object with a mass of `5 kg` is on a surface with a kinetic friction coefficient of `3`. How much force is necessary to accelerate the object horizontally at `7 m/s^2`?

Answer 1

The force is `=182N`

Explanation:

The coefficient of friction is

`mu_k=F_r/N`

The frictional force is `F_r`

The normal force is `N=mg`

The net force on the object is `=F`

According to Newton's Second Law

`F-F_r=ma`

`F-mu_kN=ma`

`F=mu_kmg+ma=m(mu_kg+a)`

`mu_k=3`

`a=7ms^-2`

`m=5kg`

Therefore,

`F=5(3*9.8+7)=182N`