Tennis Ball In the Air

[GWS]

Vanessa throws a tennis ball in the air. The function
h(t) = –16t^2 + 45t + 7 represents the distance, in feet, that
the ball is from the ground at any time t. At what time, to the
nearest tenth of a second, is the ball at its maximum height?

 

[soroban]

Hello, GWS!

Vanessa throws a tennis ball in the air.
The function, $\displaystyle h(t)\:=\: -16t^2\,+\,45t\,+\,7$ represents the distance, in feet,
that the ball is from the ground at any time t
At what time, to the nearest tenth of a second, is the ball at its maximum height?

The graph is a down-opening parabola . . . $\displaystyle \;\;$Hence, its maximum is at its vertex.

You're expected to know how to find the vertex of a parabola.

 

[Guest]

Okay you have to complete the square to do this. The answer to the maximum height is the number you get at the very end of the equation.

 

[GWS]

ok

Thank you both for your help.