A runner whose mass is around 45 kg accelerates from a stop to a speed of 8 m/s in 2 seconds. (An excellent sprinter can run 100 meters in around 10 seconds having an average speed of 10 m/s.)
(i) Determine the average horizontal component of the force which the ground applies on the runner's shoes?
(ii) Determine how much displacement is there of the force which acts on the sole of the runner's shoes, supposing that there is no slipping?
(iii) Thus, how much work is done on the real system (the runner) by the force you computed in part (ii)?