Height h=32t-16t² where t is time and acceleration due to gravity is 32 ft/sec² acting against the velocity of the ball kicked into the air. This equation can be rewritten: h=16(2t-t²)=16(1-1+2t-t²)=16-(1-t)². When t=1 the ball reaches maximum height of 16 ft, because nothing is subtracted from 16, whereas all other values of t reduce 16.