Answer:
Explanation:
One thing we need to remember is that at the max height of parabolic motion, the velocity is 0 (because the object has to stop for a millisecond in the air to turn around and head back down). Use the one-dimensional motion equation
v = vā + at and filling in:
0 = 30 + (-9.8)(t) and
-30 = -9.8t so
t = 3 seconds
