The height h, in feet, of a projectile t seconds after launch is modeled by the equation h = 32t – 16t2. how long after launch does the projectile return to the ground?
a) 2 seconds
b) 4 seconds
c) 14 seconds
d) 16 seconds

When it returns to the ground, h = 0
32t - 16t^2 = 0
t(32 - 16t) = 0
t = 0 or 32 = 16t
t = 0 or t = 2

Therefore, the projectile returns to the ground after 2 seconds.

We are given with the projectile function expressed as h = 32t – 16t2. To get the time of flight, we differentiate the function and then equate to zero. This is equal to dh/dt = 32 - 32t = 0 ; t is equal to 1 second. The total time is twice the first-half time equal to 2 seconds.