Question

A block of mass 2kg is released from A on the track that is one quadrant of a circle of radius 1m. It slides down the track and reaches B with a speed of $4 m s ^ { - 1 }$ and finally stops at C at a distance of 3m from B. The work done against the force of friction is

• A. 10 J
• B. 20 J
• C. 2 J
• D. 6 J

Answer 1

Answer: (B)

20 J

Answer 2

Block possess potential energy at point A = mgh

Finally block stops at point C. So its total energy goes against friction i.e. work done against friction is 20 J.