Question

A plate of mass M is placed on a horizontal frictionless surface (see figure) and a body of mass m is placed on this plate. The coefficient of dynamics friction between this body and the plate is μ. If a force 2 μmg is applied to the body of mass m along the horizontal, the acceleration of the plate will be

• A. $\frac{\mu m}{M}g$
• B. $\frac{\mu m}{M+m}g$
• C. $\frac{2\mu m}{M}g$
• D. $\frac{2\mu m}{M+m}g$

Answer 1

The correct option is A $\frac{\mu m}{M}g$

Reaction on m is mg. Maximum friction force by m on M is μmg. So, the force on M is μmg forword.

Acceleration =