Hi there!
Because of Newton's Third Law, the force exerted by the sprinter on the track is equal and opposite to the force exerted by the track on the sprinter.
We can begin by calculating the sprinter's acceleration. Use the equation:
vf² = vi² + 2ad
Rearrange for acceleration:
(vf² - vi²)/2d = a
Plug in values:
(8² - 2²)/2(2.5) = 60/5 = 12 m/s²
Calculate the force:
∑F = ma
∑F = 60 × 12 = 720 N. This is the amount of force exerted by the track on the sprinter in causing him to accelerate forward.
Thus, the backward force exerted by the sprinter on the track is the opposite, or -720 N.