Aprojectile is thrown upward so that its distance above the ground after t seconds is given by the function h(t) = -16t^2 + 640t. after how many seconds does the projectile take to reach its maximum height?

time taken, t = 20 seconds

Explanation:

It is given that, a projectile is thrown upward so that its distance above the ground after t seconds is given by the function as :

.....(1)

t be the time taken to reach its maximum height.

For maximum height,  

After solving, we get t = 20 seconds

Putting the value of t is equation (1) as :

h(t) = 6400 meters

Hence, the time taken to reach its maximum height is 20 seconds.

3.2x10^7