A sprinter runs 100 meters at a speed of 7 meters per second. Then she cools down by running 100 meters at 3.5 meters per second. What is the best prediction?

Question

KE=12mv2

Answer 1

The best prediction is that the kinetic energy of the sprinter during the sprint and cooldown will be different.

During the sprint, the sprinter is running at a speed of 7 meters per second. Let's assume her mass is 1 kg for simplicity.

KE (during sprint) = 12 * 1 * (7^2) = 588 Joules

During the cooldown, the sprinter is running at a speed of 3.5 meters per second.

KE (during cooldown) = 12 * 1 * (3.5^2) = 147 Joules

Therefore, the prediction is that the sprinter will have a higher kinetic energy during the sprint (588 Joules) compared to the cooldown (147 Joules).