Question

A block of mass M is pulled along a horizontal frictionless surface by a rope of mass M/2. If a force 2Mg is applied at one end of the rope, the force which the rope exerts on the block is:

• A. (2Mg)/(3)
• B. 2Mg
• C. (4Mg)/(3)
• D. zero

Hint:

For a massive rope, always consider acceleration of the entire system.

Answer 1

The Correct Option is C

Step 1: Total mass of system, M + (M)/(2) = (3M)/(2)
Step 2: Acceleration of system, a = (2Mg)/(3M/2) = (4g)/(3)
Step 3: Force exerted by rope on block, F = Ma = M · (4g)/(3) = (4Mg)/(3)