Question

A 6.0-kg ball is sliding to the right at 25.0m/s and strikes a second ball (15-kg) that is initially at rest head-on. After the collision, the 6-kg ball moves to the left at 12.5m/s. What is velocity of the second ball?
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Answer 1

Answer:

15 m/s to the right

Explanation:

Let's say right is positive and left is negative.

Momentum is conserved:

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

(6.0 kg) (25.0 m/s) + (15 kg) (0 m/s) = (6.0 kg) (-12.5 m/s) + (15 kg) v₂

v₂ = 15 m/s