Physics - NLM Question with Solution | TestHub

Block A's vertical acceleration: $a^{\prime }=a\sin \theta$, so $m{a}^{\prime }=mg-N\Rightarrow N=m(g-a\sin \theta )$ - (A) wrong.

Relative to B, A slides down the incline with acceleration $a\cos \theta$ - (B)

For no relative motion: friction $f=ma\cos \theta$ and $\mu N\ge f$.

${\mu }_{min}=\frac{a\cos \theta }{g-a\sin \theta }$ - (D) correct, (C) wrong.