Initial velocity is 21 m/s, the angle is 40 degrees, 20 meters away from the wall. How long is the ball in the air for?
Vo = 21m/s[40o]
Xo = 31*Cos40 = 16.1 m/s.
Range=Vo^2*sin(2A)/g = 21^2*sin(80)/9.8
= 44.3 m.
Range = Xo*T = 44.3 m.
16.1T = 44.3
T = 2.75 s. = Time in air.