# An object with a mass of #7 kg# is pushed along a linear path with a kinetic friction coefficient of #u_k(x)= 1+x-xcos(x) #. How much work would it take to move the object over #x in [0, 4pi], where x is in meters?

##### 1 Answer

#### Answer:

#### Explanation:

the simple idea here is that Work = Force

The work is being done against friction, and here, we have for the friction force....

where

so

The work is being done against friction **along a linear path** ; and thus...

The red term can be done by IBP, ie

We have

so

So