A projectile is launched from a platform 15 feet high with a

A projectile is launched from a platform 15 feet high with an initial velocity of 96 feet per second. The height h of the projectile at t seconds after launch is given by h = - 16t^2 + 96t + 15 feet. How many seconds after launch does the projectile attain maximum height? Show work. What is the maximum height? Show work.

Solution

h = -16t^2 + 96t + 15

For maximum height ======> dh/dt = 0

-32t + 96 = 0

t = 96/32 = 3 sec

b) Max height = h = -16*9 + 96*3 + 15 = 159 feet