Question

A ball is kicked upward with an initial velocity of 56 feet per second. The ball's height, h (in feet), from the ground is modeled by h-16t2+56t where t is measured in seconds. What is the practical domain in this situation?

Answer 1

h = -16t² + 56t

0 = -16t² + 56t

0 = -16t(t - 4)

0 = -16t     0 = t - 4

0 = t          4 = t

Domain: 0 ≤ t ≤ 4       Interval Notation: [0, 4]

NOTE: 0 seconds is the moment the ball is being kicked.  4 seconds is the moment it lands on the ground.