Question 24873
a)  s=-16t2+v0t


b)  s=-16(1)2+(64)(1)
    s=-16+64
    s=48 feet


c)  Ball will hit the ground when s=0.
    0=-16t2+(64)t
    0=-16t(t-4)
    The two solutions for this equation are t=0 and t=4.  Therefore, we now know that the ball will hit the ground after 4 seconds.  We can ignore the t=0 as meaningless.


d)  We know that the ball will reach its maximum height halfway through its flight.  What is that?  Half of 4 seconds is 2.
s=-16t2+v0t
s=-16(2)2+(64)(2)
s=-64+128=64 feet


I hope that I did the math correctly.