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Two identical billiard balls have velocities of 2 m/s and −1 m/s when they meet in an elastic head‑on collisio?
Two identical billiard balls have velocities of 2 m/s and −1 m/s when they meet in an elastic head‑on collision. What is the final velocity of the first ball after collision?
Answer - 0.5 m/s
- 1 m/s
+ 1 m/s
- 2 m/s
2 Answers
- PearlsawmeLv 79 years agoFavorite Answer
Since masses are equal
( u1 + u2 ) = (v1 + v2)
2-1 = 1 = (v1+v2) ----------------1
Since the collision is elastic
(u1² + u2²) = (v1² + v2²)
4 +1 = 5 = v1² + v2²
From 1,
v1² + (1-v1) ² = 5
v1² + (1-2v1 + v1²) = 5
v1² -v1 - 2 = 0
v1 = -1 or 2
Since 2 is not given in the choice,
the answer is -1m/s
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- Anonymous9 years ago
+1 m/s
Source(s): Tim Tebow
