# If a #6kg# object moving at #4 m/s# slows down to a halt after moving 12 m, what is the friction coefficient of the surface that the object was moving over?

##### 1 Answer

#### Answer:

#### Explanation:

Given that the object was moving over a friction surface at a speed of

First we need to find the de-acceleration the object suffered. We'll use the third kinematic equation to solve this.

So,

So,

The negative sign makes sense, since the object is decelerating.

Now, we know that the object is moving over the friction surface is being acted upon by a frictional force that is proportional to the force the object acts on the surface of friction.

i.e

We also know that this force is the same force that causes the de-acceleration on the object. So, that means

Equating the two, we get

So,

So substituting the values you'll see what