Two boys are throwing a baseball bat back and forth. the ball is 4ft above the ground when it leaves one child's hand with an upward velocity of 36ft/s. if acceleration due to gravity is -16ft/s^2, how high above the ground is the ball 2 s after it is thrown?
a) 12ft
b) 20ft
c) 76ft
d) 116ft

That's a typo...if the acceleration of gravity is -16ft/s^2???  Maybe basketball on Mars :P

Free fall equation result from integration of the acceleration equation with respect to time...

a=g

v=gt+v0

h=gt^2/2+v0t+h0 where v0 and h0 are initial velocity and height respectively..

Since acceleration, g, is about -32ft/s^2 not -16ft/s^2 you get:

h=-16t^2+36t+4 for your height equation. 

h(2)=12 ft