JEE Main 2019 Physics question
A man (mass = 50 kg) and his son (mass = 20 kg) are standing on a frictionless surface facing each other. The man pushes his son so that he starts moving at a speed of 0.70 ms with respect to the man. The speed of the man with respect to the surface is:
Answer: (C)
Solution
50v = 20u and u + v = 0.7 ⇒ v = 0.2 m/s.