Question

A block of mass $M$ is pulled along a horizontal frictionless surface by a rope of mass $m$. If a force $P$ is applied at the free end of the rope, the force exerted by the rope on the block is

• A. $\frac{Pm}{M+m}$
• B. $\frac{Pm}{M-m}$
• C. $P$
• D. $\frac{PM}{M+m}$

Answer 1

Answer: (D)

$\frac{PM}{M+m}$

Answer 2

Let acceleration of system (rope + block) is an along the direction of applied force. Then $a=\frac{P}{M+m}$ Draw the FBD of block and rope as shown in figure.where, $T$ is the required parameter For block $T=Ma$ $\Rightarrow$ $T=\frac{MP}{M+m}$