Question

The equation for a projectile's height versus time is h(t)=-16t^2+Vt+h.

A tennis ball machine serves a ball vertically into the air from a height of 2 feet, with an initial speed of 120 feet per second. After how many seconds does the ball attain its maximum height.

Round to the nearest hundred.

Answer 1

3.75 seconds

Explanation:

Given:

`h(t)=-16t^2+Vt+h`

`h=2`

`V=180`

Plug in given info into formula:

`h(t)=-16t^2+120t+2`

Find the x-coordinate of the vertex:

`t=-(b)/(2a)`

`t=-(120)/(2(-16))`

`t=-(120)/(-32)`

`t=(15)/(4)`

`t=3.75`