Question

If an object is moving at `15 m/s` over a surface with a kinetic friction coefficient of `u_k=5 /g`, how far will the object continue to move?

Answer 1

The distance is `=22.5m`

Explanation:

Let the mass of the object be `=mkg`

Then,

the coefficient of friction is

`mu_k=F_r/N`

`N=mg`

So,

`F_r=mu_k*N=5/g*mg=5m`

We apply Newton's Second Law

`F=ma=5m`

The deceleration is `=5ms^-2`

We apply the equation of motion

`v^2=u^2+2as`

`v=0`

`u=15ms^-1`

`a=-5ms^-2`

`0=15^2-2*5*s`

`s=15^2/10=22.5m`