Posted by **confused** on Monday, November 22, 2010 at 6:55pm.

Sprinting near the end of a race, a runner with a mass of 70 kg accelerates from a speed of 6 m/s to a speed of 9 m/s in 2 s.

(a) What is the runner's average acceleration during this time?

(b) To gain speed the runner produces a backward force on the ground, so that the ground pushes the runner forward providing the force necessary for acceleration. Calculate this average force.

- physics -
**Normen**, Friday, January 10, 2014 at 10:32pm
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