Question

DeSean throws a ball up with an initial vertical velocity of 30 ft/s from a platform that is at ground level. How long will the ball be in the air?

Answer 1

h=h+vi t-4.9t^2

h=h=0

0=vi t-4.9t^2= t(vi-4.9t)

t= 30/4.9 m/s

Answer 2

Answer:

Time, t = 1.875 seconds

Step-by-step explanation:

It is given that,

Initial velocity of the ball, u = 30 ft/s

DeSean throws a ball from a platform that is at ground level. The equation of motion when an object is thrown vertically upward is given by the following equation as :

$h(t)=-16t^2+vt+h$

Here, h = 0 since, the ball is thrown up at the ground level. We have to determine the time when the ball be in air. The quadratic equation becomes :

$-16t^2+30t+0=0$

t = 1.875 seconds  

So, the ball be in air for 1.875 seconds. Hence, this is the required solution.