The bonds between molecules store Energy?

chemical energy

Explanation:

Energy is also stored in the covalent bonds holding atoms together in molecules. ... the difference in the amount of free energy given off as the original, reacting molecules fly apart, and the amount of free energy absorbed as the new covalent bonds form is left in the environment, often as light and/or heat.

prolly a beacuse the momentuem the car has increases while going down hill