Question Constellation Sign up for free AQA · GCSE · Combined Science · Higher
Two skaters and momentum conservation
Skater A bumps into another skater, Skater B. Skater B is stationary. The skaters move off together in a straight line. Explain what happens to the velocity of each of the skaters. Use the idea of conservation of momentum.
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Marking points
- 1 State that total momentum before the collision equals total momentum after the collision.
- 2 Explain that skater A loses momentum and skater B gains momentum, or that the total momentum is shared between them.
- 3 State that skater A's velocity decreases and skater B's velocity increases.
Full-mark answer
The total momentum before the collision equals the total momentum after the collision. After the collision the momentum is shared between the two skaters, so skater A's momentum and velocity decrease while skater B's momentum and velocity increase.
Why this answer loses marks
Both skaters speed up because momentum is conserved.
Skater A loses momentum and velocity while skater B gains momentum and velocity.