Linear kinematics

Position, average and instantaneous velocity, acceleration: describing straight-line motion.

The outline, topic by topic

Each topic is weighted the way the exam weighs it.

Kinematics: what is it?
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Describing motion without looking at its causes.
Causes, that is forces, belong to kinetics.
Two sprinters run the same 100 m time, but one leads at 50 m. What about their average speeds?
- They are equal over 100 m
- The 50 m leader's is higher over 100 m
- They cannot be compared without split times
- The other one's is higher over 100 m
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They are equal over 100 m
Same distance, same time, same average speed over 100 m. Over the first 50 m, however, the leader's is higher.
Average speed: what is it?
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Distance covered divided by time.
It hides changes during the race.
Why is average speed not enough to analyse a sprint?
- It is always above the top speed reached
- It hides the acceleration, the peak and the slowdown
- It ignores the distance covered
- It only makes sense for distance races
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It hides the acceleration, the peak and the slowdown
The speed profile shows where one gains and loses.