Collisions: momentum, kinetic energy lost and two possible outcomes
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The teaching part (1 min) is free to watch. A free account opens the whole lecture: 6 practice questions, 2 real past-paper questions with the answers explained, the mistakes that lose marks, the full-marks tip, a one-card summary and a quick quiz.
What this lecture covers
- Billiards in one dimension
- Conservation of momentum
Read the transcript of the teaching part
Last time
Before we start: last time, in Two particles, you learned these points. Here they are again on one card. Keep them in mind, because today builds on them.
Billiards in one dimension
When one billiard ball hits another, the first slows, the second speeds up, and the total push, the momentum, stays the same. But the total movement energy does not always stay the same: some is lost as sound and heat. Those two facts answer every collision question in Paper 4.
Conservation of momentum
Momentum is mass times velocity. In a collision between two particles on a smooth surface, total momentum before equals total momentum after. Pick a positive direction and keep to it. A velocity in the opposite direction is negative. When two particles stick together, they coalesce, and move with one common velocity.
How often it comes up
The whole chapter: Momentum.
Chapter 4.3: Momentum
- Collisions: momentum, kinetic energy lost and two possible outcomes 6 min
Also for A Level Maths 9709 Paper 4
Which topics come up most in A Level Maths 9709 Paper 4 past papers, counted from every paper since 2004.