Question

A mis-hit golf ball flies straight upward. It reaches a height of 31.0 meters before falling back down. How fast was it going when it was hit? (Assume you can ignore drag)

Answer 1

At the top most position when ball reach to height 31 m

The speed of the ball must be ZERO

now we can use kinematics to find the final speed of the ball when it will hit back the ground

the equation of kinematics will be

`v_f^2 - v_i^2 = 2 ad`

`v_f^2 - 0^2 = 2(9.8)(31)`

`v_f^2 = 607.6`

`v_f = 24.65 m/s`

so it will hit the ground at speed 24.65 m/s