Question

A wagon of mass $M$ has a block of mass $m$ attached to it as shown in the figure. The coefficient of friction between the block and wagon is $\mu$. The minimum acceleration of the wagon so that the block $m$ does not fall is

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

Answer 1

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

Suppose it is moving with acceleration 'a' in forward direction

In horizontal direction

$N=ma$

In vertical direction

$f=mg$

$\mu N=mg$

$\mu ma=mg$

$a=\frac{g}{\mu }$