Question
Question: A man of mass M stands at one end of a plank of length L which lies at rest on a frictionless surfac...
A man of mass M stands at one end of a plank of length L which lies at rest on a frictionless surface. The man walks to the other end of the plank. If the mass of the plank is 3M, the distance that the man moves relative to the ground is –
A
L/4
B
3L/4
C
2L/3
D
L/3
Answer
3L/4
Explanation
Solution
3mx = m (L–x) , 4mx = mLŽ x = L/4
displacement of man = L –x = L– L/4= 3L/4