Answer:
we understand it by electromagnetic spectrum. and we velength is the distance between identical location on adjecent waves ( see figure below)
The volume of water will increase . If yu subtract the original volume from the new volume of water you will get the volume of the small ball.
In this three body system total kinetic energy remains constant:


If we assume that upwards movement is positive and downwards movement is negative the formula is:

Formula for kinetic energy is:

Now we have:

We got two solutions: positive and negative. The speed is 5.04 m/s and direction can be upwards and downwards.