Question

Abbey and Mia are in the basement playing pool. On Abbey's recent shot, the cue ball was moving east at 82 cm/s when it struck the slower 5-ball moving in the same direction at 24 cm/s. The 5-ball immediately speeds up to 52 cm/s. Determine the post-collision speed of the cue ball.

Answer 1

Answer:

v₁ = 54 cm/s

Explanation:

This question can be solved using the law of conservation of momentum:

$m_1u_1+m_2u_2=m_1v_1+m_2v_2$

where,

m₁ = m₂ = m = mass of both balls

u₁ = pre-collision speed of cue ball = 82 cm/s

u₂ = pre-collision speed of 5-ball = 24 cm/s

v₁ = post-collision speed of cue ball = ?

v₂ = post-collision speed of 5-ball = 52 cm/s

Therefore,

$m(82\ cm/s)+m(24\ cm/s)=m(v_1)+m(52\ cm/s)\\v_1 = 82\ cm/s + 24\ cm/s - 52\ cm/s$

v₁ = 54 cm/s