Aball is kicked straight up from ground level at a velocity of 13 m/s. find:
a) the maximum height
b) the time at which the ball reaches maximum height
c) the time required for the entire trip
d) the ball's velocity just before it hits the ground upon returning

1. the max height is solved from v = square root of 2 gy where g is equal to 9.8 m/s2/ hence y is equal to 8.62 meters. 

 2. time at max height is solve when velocity = 0. ( 0 = -9.81*t +13); t = 1.325 seconds 

3. time required for the entire trip is 2*1.325 equal to 2.65 seconds. 

4. without air resistance, the velocity just before the ball hits the ground is the same as its initial velocity, 13 m/s.