In the figure, a constant external force P = 160 N is applied to a 20.0-kg box, which is on a rough horizontal surface. While the force pushes the box a distance of 8.00 m, the speed changes from 0.500 m/s to 2.60 m/s. What ia the work done by friction during this process?
![1166_A constant external force P.png](https://secure.tutorsglobe.com/CMSImages/1166_A constant external force P.png)