Answer:
No non-conservative forces, such as friction, act between objects within the system
Step-by-step explanation:
The law of conservation of mechanical energy in a closed system states that;'The total amount of mechanical energy, in a closed system in the absence of non-conservative forces, such as friction, remains constant.' Non-conservative forces cause energy to be lost from the system, this lost energy can't be gotten back
This implication of this is that energy can not disappear. Kinetic energy can be converted into potential energy and vice-versa in accordance with this principle.