Final answer:
Mechanical energy is conserved when something transitions from potential to kinetic energy and back, assuming no loss due to friction or other non-conservative forces, following the Law of Conservation of Mechanical Energy. Therefore, the correct answer is A) Yes.
Step-by-step explanation:
If something goes from potential energy to kinetic energy to potential energy, is mechanical energy conserved? The answer to this question is generally yes, mechanical energy is conserved in such a process, assuming there is no energy loss due to friction or other non-conservative forces.
The Law of Conservation of Mechanical Energy states that in a closed system, without external dissipative forces, the sum of potential and kinetic energy (mechanical energy) will remain constant.
For example, consider a roller coaster that has many ups and downs. As long as we assume no energy is lost to friction, then at any point during the ride, the total mechanical energy remains the same as it was at the very top of the first hill.
The car's potential energy transforms into kinetic energy as it speeds up and back into potential energy as it slows down reaching the top of the next hill. This transformation is a reflection of the law of conservation of energy, stating that energy cannot simply 'disappear'.