Question

bodies of masses 'm' and '3m', moving with velocities 3v and v respectively along same direction, collide with each other. After collision they stick together and move with a velocity V in the same direction. Then find the final velocity.

Answer 1

Given :

▪ Mass of body A = m

▪ Mass of body B = 3m

▪ Velocity of body A = 3v

▪ Velocity of body B = v

▪ They stick together after collision.

To Find :

▪ Final velocity (V) of the combined mass.

Concept :

☞ Since, no net force acts on the whole system, we can easily apply concept of linear momentum conservation to solve this type of questions.

☞ Initial momentum of the system = Final momentum of the system

Calculation :

→ (P)initial = (P)final

→ (P)A + (P)B = (P)final

→ (3m×v) + (m×3v) = (3m+m)V

→ 3mv + 3mv = 4mV

→ 6mv = 4mV

→ V = 6v/4

→ V = 3v/2

→ V = 1.5v