Question

A man of 60 kg is running on the road and suddenly jumps into a stationary trolly car of mass 120 kg. Then, the trolly car starts moving with velocity 2ms-1. The velocity of the running man was _____ ms-1, when he jumps into the car.

Answer 1

The correct answer is 6
By taking the system as man and trolley and using conservation of linear momentum :
$v_m = \frac{(120+60)v_T}{60}$
$= \frac{180 × 2}{60}$
= 6 m/s