A 22-Kg Block Starts from Rest on a Rough Inclined Plane

Multiple Choice

A 2.2-kg block starts from rest on a rough inclined plane that makes an angle of 25 ° with the horizontal. The coefficient of kinetic friction is 0.25. As the block goes 2.0 m down the plane, the mechanical energy of the Earth-block system changes by:

A) 0
B) -9.8 J
C) 9.8 J
D) -18 J
E) 18 J