Question

A moving body of mass m and velocity 3 kg/hour
collides with a rest body of mass 2m and sticks
to it. Now the combined mass starts to move.
What will be the combined velocity :
(a) 1 km/hour (b) 2 km/hour
(c) 3 km/hour (d) 4 km/hour​

Answer 1

Answer:

Let u be the inital velocity of mass m and v be the velocity of combined mass.

From the conservation of momentum,

⇒mu=(m+2m)v

⇒v=

3

u

=1 km/h