Answer
a) $-5.12$ $m/s$
b) $-7.25$ $m/s$
Work Step by Step
a)
$v(t)$ = $-\sqrt {\frac{m}{k}[a(t)+9.8]}$
$a(t)$ = $-4.9$
$v(t)$ = $-\sqrt {\frac{75}{14}[-4.9+9.8]}$ = $-5.12$ $m/s$
b)
$a(t)$ = $0$
$v(t)$ = $-\sqrt {\frac{75}{14}[0+9.8]}$ = $-7.25$ $m/s$
