If a second ball were dropped from rest from height ymax, how long would it take to reach the ground

Explanation:

Given

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Required

How long to reach the ground from the maximum height

First, calculate the time of flight (T)

The time taken (t) from maximum height to the ground is:

So, we have:

Another representation is:

At ymax, the time is: t1

On the ground, the time is t2

The difference between these times is the time taken.

So;

Since air resistance is to be ignored, then

--- i.e. time to reach the maximum height from the ground equals time to reach the ground from the maximum height