Question

A man weighing 60kg runs along the rails with a velocity of 18 km/h and jumps in to a car
of mass 1 quintal (100kg) standing on the rails . calculate the velocity with which car will start travelling along the rails.

Answer 1

use law of conservation of momentum ...m1 =60kg, u1=18kmps or 5mps, m2=100,u2=0,

so, m1u1+m2u2=(m1+m2) v , where v is final velocity of system.
puttin values ..
v=30/16 ≈ 1.8 mps