Question

A $50kg$ person stands on a $25kg$ platform. He pulls on the rope which is attached to the platform via frictionless pulleys as shown in the figure. The platform moves upward at a steady rate. The force with which the person pulls the rope is :

• A. 500 N
• B. 250 N
• C. 25 N
• D. 50 N

Answer 1

Answer: (B)

250 N

Answer is B
From the F.B.D of man,
50g-T=N (i)
From the F.B.D of platform,
2T-N=25g (ii)
From i and ii
T=25g= 250N
Question can be solved in other way also,
Considering the man and platform as a single system,
upward force= downward force
or, 3T= (50+25)g
T=25g= 250N