Given $s(t)=5t^2+15t,$ find

$($a$)v(t).$

$($b$)a(t).$

$($c$)$ the velocity and acceleration when $t=2.$

$($a$)v(t)=$

$($b$)a(t)=$

$($c$)$ When $t=2,$ the velocity is $$ feet per second.

$($Simplify your answer.$)$

When $t=2,$ the acceleration is $$ feet per second squared. $($Simplify your answer.$)$