Question

In the given arrangement, mass of the block is M and the surface on which the block is placed is smooth. Assume all pulleys to be massless and frictionless, strings to be inelastic and light, $R_1,R_2$ and $R_3$ to be light supporting rods. The acceleration of point P will be (A is fixed) :

• A. 0
• B. $\infty$
• C. $\frac{4F}{M}$
• D. $\frac{2F}{M}$

Answer 1

The correct option is C $\frac{4F}{M}$

Since the String is inelastic and light, at point $P$

$T=F$

The tension in the strings will be distributed as per the given figure because the pulleys are massless.

$Ma=2T=2F\Rightarrow a=\frac{2F}{M}$

Point $P$ will move with double rate as compared to mass $M$

so, acceleration of point P is 2a and thus we get $\frac{4F}{M}$