About the movement of a cube and a sphere on a plane

[davon806]

A spherical or cylindrical object would roll on a plane.
However,object with other shapes(e.g. A cube or a retangular object) would slide on a plane.
Why?

 

[AJ Bentley]

Because:-
When a cylinder/sphere rolls, it's centre of mass stays at the same height so only a little bit of energy is needed to move it.

But to 'roll' a cube, you have to lift the centre of mass over the corner. That takes a lot of energy. If you push a cube very hard and give it plenty of energy, it will roll. (Think of dice)