Question

A long plank of mass m is initially at rest on a fictionless surface. A small block with mass initial speed \(u_0\) slides on top of the larger plank. The coefficient of friction between the block plank is \(\mu\). Net work done by friction on system if the top block falls off the plank after sliding on length L is

• A. $-\mu MgL$
• B. $-\mu \left(\frac{M+m}{M}\right)gL$
• C. $-\mu \left(\frac{M}{M+m}\right)gL$
• D. $-\mu mgL$

Answer 1

The correct option is D $-\mu mgL$

$W=\overline{f}.\overline{dx}$