Question

how is energy conserved in mechanical systems?
mechanical energy is...
the amount of kinetic and potential energy in the system (can / cannot) change, but the total amount of mechanical energy (can / cannot) change.
other information:
energy: conservation of energy
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Explanation:

In a mechanical system, kinetic and potential energy can inter - convert. For example, in a roller - coaster (as in the image), at the top of a hill, it has more potential energy (due to height) and less kinetic energy (low speed). As it goes down, potential energy decreases and kinetic energy increases. But according to the law of conservation of mechanical energy (in the absence of non - conservative forces like friction), the sum of kinetic energy \(K\) and potential energy \(U\), i.e., \(E = K + U\) remains constant.

Answer:

The amount of kinetic and potential energy in the system (can) change, but the total amount of mechanical energy (cannot) change.