Physics - NLM Question with Solution | TestHub

Since $m$ remains stuck to $M$, the acceleration of both blocks must be the same; let it be $a$.

FBD of $m$:

From FBD of $m$:

$$\begin{array}{rl}N& =ma\\ \mu N& =mg\\ \mu ma& =mg\\ a& =\frac{g}{\mu }\end{array}$$

This is the minimum acceleration with which $M$ should move so that $m$ remains stuck.