MOMENTUM
2 marks · EasyA sprinter of mass 70 kg is running at a velocity of 8 m/s. She slows down to a stop in 4 seconds. Calculate her change in momentum and the average force needed to stop her.
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Change in momentum = 560 kg m/s; Force = 140 N
Common mistakes: Subtracting final velocity from initial the wrong way around; Forgetting negative sign; Mixing up formulae
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Marking points
M1 · 1 mark · Correct calculation of change in momentum. (follow-through)
A1 · 1 mark · Correct calculation of average force using the correct formula. (follow-through)
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