A football is kicked at ground level with a speed of 15.0 m/s at an angle of 39.0° to the horizontal. How much later does it hit the ground?
Vo = 15m/s[39o].
Yo = 15*sin39 = 9.44 m/s.
Y = Yo + g*Tr = 0 @ h max.
9.44 - 9.8Tr = 0.
Tr = 9.44/9.8 = 0.96 s. = Rise time.
Tf = Tr = 0.96 s. = Fall time.
T = Tr+Tf = 0.96 + 0.96 = 1.92 s.