A projectile is launched straight up from ground level with an initial velocity of v0 per…

A projectile is launched straight up from ground level with an
initial velocity of v0 per sec. Neglecting air
resistance, its height in feet, s, after t
seconds after launch is given by the equation

s = –16t2
+ v0t.

At what time(s) will the projectile reach a height of 112 feet
when v0 = 96 feet/sec?
After how many seconds will it return to the ground when
v0 = 96 feet/sec?