Answer
$h_{alt}=314$ m
$v=72.5$ m/s
Work Step by Step
$(+\downarrow)$
$s=s_0+v_0t+\frac{1}{2}a_ct^2$
$h=0+(-6)(8)+\frac{1}{2}(9.81)(8)^2$
$h=265.92m$
During $t=8$s, the balloon rises
$h'=vt=6(8)=48$ m
$h_{alt}=h+h'=265.92+48=314$ m
$(+\downarrow)$
$v=v_0+a_ct$
$v=-6+9.81(8)=72.5$ m/s
