A ball of mass 0.5kg moving at 10ms¯¹ collides with another ball of equal mass at rest. If the two balls move off together after the impact, calculate their common velocity.

A. 0.2ms⁻¹
B. 0.5ms⁻¹
C. 5.0ms⁻¹
D. 5.5ms⁻¹

Correct Answer:

Option C = 5.0ms⁻¹

Explanation

Using; m₁u₁ + m₂u₂ = (m₁ + m₂)v

m₁ = 0.5kg, u₁ = 10ms1, m₂ = 0.5kg, u₂ = 0

∴ (0.5kg x 10) + (0.5 x 0) = (0.5 + 0.5)v

v = 5ms⁻¹