# If a #13 kg# object moving at #7 m/s# slows down to a halt after moving #10 m#, what is the friction coefficient of the surface that the object was moving over?

##### 1 Answer

#### Answer:

#### Explanation:

I will show you 2 different methods to do this question :

**1. Method 1 - Using Newton's Laws and Equations of Motion :**

The acceleration of the object is uniform and in 1 direction and can be found from a relevant equation of motion for constant acceleration in 1 dimension as follows :

This is acceleration is caused by the frictional force which is the resultant force acting on the object and so by Newton 2 and definition of frictional forces we get :

But

**2. Method 2 - Using energy considerations :**

The Work-Energy Theorem states that the work done by the resultant force equals the change in kinetic energy brought about.