In a forward punch in karate, the fist begins at rest at the waist and is brought rapidly forward until the arm is fully extended. The speed $v(t)$ of the fist is given in Fig. $2-37$ for someone skilled in karate. The vertical scaling is set by $v_{x}=8.0 \mathrm{~m} / \mathrm{s}$. How far has the fist moved at (a) time $t=50 \mathrm{~ms}$ and (b) when the speed of the fist is maximum?