Question
Question: A uniform chain of length L and mass M is lying on a smooth table and one-third of its length is han...
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 acceleration due to gravity, the work required to pull the hanging part on to the table is –
A
MgL
B
MgL/3
C
MgL/9
D
MgL/18
Answer
MgL/18
Explanation
Solution
Mass of hanging portion is (one-third) and centre of mass c, is at a distance h =
below the table top.
Therefore, the required work done is,
W = mgh =18MgL