Question

An object with mass 1Kg travels at 3m/s and collides with a stationary object whose mass is 0.5kg. The two objects stick together and continue to move. What is the velocity of the two objects together after collision?

a) 2 m/s

b) 3 m/s

c) 1 m/s

d) 4 m/s

Answer 1

Mass of the first object = m₁ = 1 kg

Mass of the second object = m₂ = 0.5 kg

Initial velocity of the first object = V₁ = 3 m/s

Initial velocity of the second object = V₂ = 0 m/s (At rest)

The two objects stick together after the collision therefore the objects will have same velocity after the collision.

Velocity of the objects after the collision = V₃

By conservation of linear momentum,

m₁V₁ + m₂V₂ = (m₁ + m₂)V₃

(1)(3) + (0.5)(0) = (1 + 0.5)V₃

V₃ = 2 m/s

Velocity of the two objects together after the collision = 2 m/s