# What is the instantaneous velocity of the ball at t=2 seconds if a ball is thrown in the air and its height from the ground in meters after t seconds is modeled by h(t)=-5t2+20t+1?

$h = 21 m$.
It is sufficient to substitue $t = 2$ in that equation:
$h \left(2\right) = - 5 \cdot {2}^{2} + 20 \cdot 2 + 1 = 21 m$.