Answer
(a) Average speed is $6\,\mathrm{m/s}$.
(b) Average velocity is $0$.
Work Step by Step
(a) The ball goes up and comes down. Net distance traveled is $d=7.1\times 2=14.4\,\mathrm{m}$.
Total time, $t=2.4\,\mathrm{s}$.
Average speed, $s=\frac{d}{t}=\frac{14.4}{2.4}=6\,\mathrm{m/s}$.
(b) The ball is caught at the same height from which it was thrown. Thus, net displacement, $x=0$.
Average velocity, $v=\frac{x}{t}=0$.
