Question

Suppose a soccer ball is kicked from the ground at an angle 20.0º above the horizontal at 8.00 m/s. The y-velocity is determined to be 2.74 m/s. How long will the ball be in the air? Assume the ball lands at the same height at which it was kicked.

Answer 1

initial speed of the ball by which it is kicked is 8 m/s

now the angle at which it is kicked is 20 degree

here we will have

`v_y = v sin20`

`v_y = 8 sin20 = 2.74 m/s`

now we will have

`\Delta y = v_y t + (1)/(2)at^2`

so if the ball again land on the ground at same level then we have

`\Delta y = 0`

`0 = 2.74 t - (1)/(2)(9.8) t^2`

`0 = 2.74 - 4.9 t`

`t = 0.56 s`

so total time will be 0.56 s