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A football player kicks a ball at ball at an angle of `30 ^(0)` with the horizontal with an initial speed of `20 m//s`. Assuming that the ball travels in a vertical plance, calculate (a) the time at which the ball reaches the highest point (b) maximum height reached (c ) the horizontal range of the ball (d) the time for which the ball is in air. `g =10 m//s^(2)`. |
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Answer» Here, `theta =30 ^(@), u=20 m//s` (a) Time taken by ball to reach the highest point, `t T/2 =(u sin theta)/g =(20)/(10) xx isn 30^(0) =xx (1//2) =1 s` (b) The maximum height `=(u^(2) sin ^(2) xx theta)/(2g) =((20)^(2) xx sing ^(2) xx sin ^(2) 30^(0))/(2xx10) =5m` (c ) The borixontal rane `=(u^(2) sin ^(2) xx theta)/(g) =((20)^(2) xx sing ^(2) xx sin ^(2) 30^(0))/(10) =34.64 m. (d) The time of flotht `=(2 usin) theta)/g =(2 xx 20xx sin 30^(0))/(10) =2 s. |
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