Why does water tend to sink near arctic regions

It's actually the opposite. In the arctic tundra water doesn't sink because the soil beneath it is frozen.

Soil beneath it sinks

When the ball is rising up, it gains kinetic energy. when the ball reaches the very top, it will have all potential energy, until it falls back down and gains it kinetic energy. finally when you catch the ball or it falls back down, it would have gained its potential energy back.

This is a time line from 685 to 978