Question

A pumpkin is launched directly upwards at 72 feet per second from a platform 24 feet high. The pumpkins height, h, at time t seconds can be represented by the equation h(t) = -16t^2+ 72t +24.Find the maximum height of the pumpkin and the time it takes to reach this point.

Answer 1

Answer: Maximum height =  105 feet

And, It takes 9/4 seconds to reach that point.

Step-by-step explanation:

Here the given function that shows the height of the pumpkin,

$h(t) = -16t^2 + 72t + 24$ --------(1)

Where t is the time in second.

Differentiating equation (1) with respect to t,

We get,    $h'(t) = -32 t + 72$

Again differentiating above equation with respect to t,

We get,   $h''(t) = -32$

For maximum or minimum,    $h'(t) = 0$

$- 32 t + 72 = 0$

$32 t = 72$

$t = \frac{9}{4}$

At t = 9/4 , h''(t) = Negative value,

Therefore, At t = 9/4 seconds, h(t) is maximum,

And, the maximum value is,

$h(\frac{9}{4} ) = -16(\frac{9}{4})^2 + 72(\frac{9}{4}) + 24$

$h(\frac{9}{4} ) = -16(\frac{81}{16})+ 72(\frac{9}{4}) + 24$

$h(\frac{9}{4} ) = -81 + 162 + 24=105$

Therefore, the maximum height of the pumpkin is 105 feet at 9/4 seconds