Question

A sprinter with a mass of 80kg accelerates from 0m/s to 9 m/s in 3 sec. What is the runners acceleration? The net force of the runner? And how far did the sprinter go in 3s?

Answer 1

Runner's acceleration:\[a=\frac{\Delta v}{\Delta t}=\frac{9-0}{3}=3\frac{m}{sec^2}\]The net force:\[F=ma=80\times3=240~N\]Distance traveled within 3 sec:\[s=v_0t+\frac{1}{2}at^2=\cancel{v_0t}^0+(0.5)(3)(3)^2=1.5(9)=13.5~m\]