A football player kicks a ball at an angle of `30^(@)` with an initial speed of 20 m/s. Assuming that the ball travel in a vertical plane, calculate
the time for which the ball is in the air. `(g = 10" m/s"^(2))`

Explanation

(a) Time taken by the ball to reach the highest point `t=(T)/(2)=(u sin theta)/(g)=(20)/(10)xxsin 30^(@)=2xx(1)/(2)=1s`
(b) The maximum height `=(u^(2)sin^(2)theta)/(g)=((20)^(2)xxsin2xx30^(@))/(10)=36.64m`
(d) The time of glight `=(2 u sin theta)/(g)=(2xx20xxsinxx30^(@))/(10)=2s`