Answer:
3.5 seconds
Step-by-step explanation:
h(t) is a quadratic function, it indicate that the object start with initial height (56).
If you want to know when the object hit the ground (h=0) you have to use the quadratic formula [tex](-b +- \sqrt{b^{2}-4ac } )/2a[/tex] and take the positive root (the negative shows a negative time, so we have to discard it).
In this case: a=-6, b=5 and c=56, then the solve is 7/2=3.5
