A football is kicked at ground level with a speed of 17.9m/s at an angle of 39.0∘ to the horizontal. How much later does it hit the ground?

Answer 1

Vo = 17.9m/s[39o]
Xo = 17.9*cos39 = 13.91 m/s.
Yo = 17.9*sin39 = 11.26 m/s.

Y = Yo + g*Tr = 0 @ max ht.
11.26 - 9.8Tr = 0
9.8Tr = 11.26
Tr = 1.15 s. = Rise time.

Tf = Tr = 1.15 s. = Fall time.

Tr+Tf = 1.15 + 1.15 = 2.30 s. = Time to
hit gnd.

Answer 2

2.30s