Question

Two blocks of mass 4 kg and 2 kg are connected by a heavy string and placed on rough horizontal plane. The 2 kg block is pulled with a constant force F. The coefficient of friction between the blocks and the ground is 0.5. What is the value of F so that tension in the string is constant throughout during the motion of the blocks : $(g=10m/s^2)$

• A. 40 N
• B. 30 N
• C. 50 N
• D. 60 N

Answer 1

The correct option is B

30 N

$T-4\mu g=4a$, for mass 4 kg
For a = 0, tension is constant throughout
$T=4\mu g=20N$ $F=T+2\mu g=30N$