A ball is thrown into the air with an upward velocity of 40 ft/s. Its height in feet after t seconds is given by the function h = -16t2 + 40t + 10. In how many seconds does it take the ball to reach its maximum height?

Question

A ball is thrown into the air with an upward velocity of 40 ft/s.  Its height in feet after t seconds is given by the function h =  -16t2 + 40t + 10.  In how many seconds does it take the ball to reach its maximum height?

tkhunny · Answer

This is a standard model.  You are expected to know WHEN the maximum value will be obtained and WHERE the maximum value is.

You've a choice.  "Complete the Square" and put the thing in Vertex Form, or you might just happen to know where the maximum value is.  Heard of -b/(2a)?

anonymous · Answer

I know what the max height is