Impulse and momentum

Impulse, momentum, cushioning landings and how long forces are applied.

The outline, topic by topic

Each topic is weighted the way the exam weighs it.

Momentum: what is it?
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Mass times velocity: p = m × v.
A charging prop is hard to stop.
A gymnast lands with straight legs and gets hurt. What should be corrected?
- Bend the legs to lengthen the braking time
- Stiffen the legs more to absorb the shock
- Shorten the contact with the floor
- Lean back at impact
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Bend the legs to lengthen the braking time
Same change in speed, longer time: smaller force (F × Δt = m × Δv).
Impulse: what is it?
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A force times how long it acts, equal to the change in momentum.
Pushing longer gives more speed.