Denise G. answered • 04/22/19

Algebra, College Algebra, Prealgebra, Precalculus, GED, ASVAB Tutor

When the rick hits the ground, the height would be 0. So plug zero in for h and then solve.

*0 = 78.4t – 4.9t*²

This can be solved by the quadratic equation, it also factors.

*0 = 4.9t(16-t)*

Setting the factors equal to zero and solving

4.9t = 0 and 16-t=0

t=0 and t=16

t=0 is when the rock, LEAVES the ground. The time it hits the ground would be **16 seconds**.