A block of mass 20 kg slides on a rough horizontal plane surface. Let the speed of the block at a particular instant is 10 m/s. It comes to rest after travelling a distance of 20 m. Which one of the following could be the magnitude of the frictional force?

Correct option is D

The correct answer is (d) 50 N. Explanation: To find the frictional force, we use the work-energy principle, where the work done by friction equals the initial kinetic energy of the block. 1. Calculate Initial Kinetic Energy: · KE = 0.5 × mass × speed² = 0.5 × 20 kg × (10 m/s)² = 1000 J 2. Calculate Frictional Force: · Work done by friction = Frictional force × distance · 1000 J = Frictional force × 20 m · Frictional force = 1000 J / 20 m = 50 N Thus, the correct frictional force is 50 N.