A small block with mass 0.0400 kg slides in a vertical circle ofradius 0.500 m on the inside of a circular track. During one of therevolutions of the block, when the block is at the bottom of itspath, point A, the magnitude of the normal force exertedon the block by the track has magnitude 4N . In this samerevolution, when the block reaches the top of its path, pointB, the magnitude of the normal force exerted on the blockhas magnitude 0.660 N .
How much work was done on the block by friction during the motionof the block from point A to point B?
