6. When water in a lake freezes, the ice that forms floats on top of any water that is still liquid. Why does the ice float?
A
Ice is less dense than liquid water, so it floats.
B.
Air bubbles trapped in the ice cause the ice to float.
C. Ice crystals are polar, and they float on top of non-polar water.
D.
The ice forms at the top of the water, so it stays there and floats.

It depends on the surface of the levels. the rougher the surface, the greater is the frictional force. for rougher surfaces, you would need to exert greater force to move the object. the concept is that, you must overcome the frictional force in order to bring the object into motion. this is the reason why we add lubricants to the joints so they could easily move. this answer was on