In a game of pool, why will the balls eventually stop after a collision?

What is the orbital period of a spacecraft in a low orbit near the surface of mars? the radius of mars is 3.4×106m.

Convection occurs when thermal energy is transferred by the movement of

The amount of heat required to change liquid water to vapor at its boiling temperature is 2256 kj/kg. the amount of heat required to change liquid mercury to its vapor state at its boiling temperature is 295 kj/kg. one kg of each substance is currently at its boiling point. how will the amount of thermal energy required to change each substance from a liquid to a gas differ?