NTA Abhyas JEE Main2020PhysicsWork, Power and EnergyPractice
A uniform chain of length L and mass M is lying on a smooth table and one-third of its length is hanging vertically down over the edge of the table. If g is the acceleration due to gravity, the work required to pull the hanging part on to the table is
Options
- AM g L
- BM g L 3
- CM g L 9
- DM g L 18
Correct answer
D. M g L 18
Step-by-step solution
Mass of hanging portion is M 3 h = L 6 below the table top. Therefore, the required work done is, W = m g h = M 3 ( g ) L 6 = M g L 18