A uniform chain of mass M and length L rests on a table with length L/n hanging over its edge. Find work required to pull the hanging part onto the table.
Options

Question

A uniform chain of mass M and length L rests on a table with length L/n hanging over its edge. Find work required to pull the hanging part onto the table.

G1 Physics · Accepted Answer

Step 1 — Principle: For a conservative force, the work is the negative change in potential energy. Step 2 — Working: Mass of hanging part is M/n; its centre lies L/(2n) below the tabletop. Step 3 — Working: Lifting the portion to tabletop increases PE by (M/n)g[L/(2n)]=MgL/(2n²). Correct answer: A — MgL/(2n²).