In convection why does the hot fluid rise in the center and the cold gas fall on the sides?

To do work, this truck uses energy stored in chemical fuel and an electrical battery. how much total energy does this truck put out?

Within a pendulum, as potential energy decreases, energy increases. a. heat b. kinetic c. frictional d. gravitational

Lightning is an example of what phenomenon? a release of a large amount of energy an absorption of a large amount of energy a natural electric circuit a natural electric current