A 3 kg trolley moving at 10 m/s collides with a stationary 2 kg trolley and the two stick together. Find their common speed.
Answer and explanation
Correct answer: C. 6 m/s
- Step 1: Momentum is conserved: .
- Step 2: , so m/s.
Answer
6 m/s.
Why not the others: 10 m/s: it assumes the speed does not change. 5 m/s: it assumes the speed is simply halved. 4 m/s: it uses the mass of the wrong trolley in the momentum.
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