Question

An object with a mass of `7 kg` is on a surface with a kinetic friction coefficient of `8`. How much force is necessary to accelerate the object horizontally at `14 m/s^2`?

Answer 1

Suppose here we will be applying externally a force of `F` and frictional force will try to oppose its motion,but as `F>f` so due to the net force `F-f` the body will accelerate with an acceleration of `a`

So,we can write,

`F-f=ma`

Given, `a=14 ms^-2,m=7Kg,mu=8`

So,`f=muN=mumg=8×7×9.8=548.8 N`

So,`F-548.8=7×14`

Or, `F=646.8N`