Question

Sarah throw a ball straight up in the air with initial velocity of 19.62m/s. how long will the ball be in the air

Answer 1

Here Sarah projected the ball upwards by speed

`v_i = 19.62 m/s`

here the acceleration is due to gravity

`a = 9.81 m/s^2`

now when ball again lends on the ground the displacement of ball will be zero

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

`0 = 19.62 t - (1)/(2)9.81*t^2`

by solving above equation

`t = 4 s`

so it will take 4 s to reach back on ground