A block of mass 1 slides down a curved track that is one quadrant of a circle of radius 1m. Its speed at the bottom is 2m/s. The work done by frictional force is:

A block of mass 1 slides down a curved track that is one quadrant of a

1.	A block of mass 1 slides down a curved track that is one quadrant of a circle of radius 1m. Its speed at the bottom is 2m/s. The work done by frictional force is:
Answer» 8J `-8J` `4J` `-4J` ANSWER :B