Problema Solution
The height of a projectile fired upward with an initial velocity of 400 feet per second is given by the formula h=-16t^2+400t where h is the height in feet and t is the time in seconds. Find the time required for the projectile to return to earth.
Answer provided by our tutors
when returning to earth, h = 0
Set h=-16t^2+400t = 0
Factoring t(-16t+400) = 0
t must not be 0
-16t + 400 = 0
t=400/16= 25