Question

Amy drops a ball from an initial height of 30 feet above the ground. After how many seconds will the ball reach the ground?

Answer 1

I got `1.3s`

Explanation:

I am not sure it is algebra but anyway...
I would use the general relationship from kinematics:

`h=v_it+1/2at^2`

where:
`h=30"ft"=9.144m~~9m`
`v_i=0` is the initial velocity;
`t=?` time;
`a=9.8m/s^2` is the acceleration of gravity.
We get:
`9=0t+9.8/2t^2`
rearranging:
`t=sqrt(18/9.8)=1.3s`