# Question #c38d7

Jan 7, 2018

$- 24$ feet per second

#### Explanation:

The displacement is given by $y = 40 t - 16 {t}^{2}$ then velocity will be the derivative of this with respect to time:

$v = \frac{\mathrm{dy}}{\mathrm{dt}} = 40 - 32 t$

Now simply substitute in $t = 2$ to get:

$40 - 32 \left(2\right) = 40 - 64 = - 24$ feet per second