Energy Test Reflection

Upon reflection on the last energy test I took, I realized that there is still a hole in my learning. I do not know how to write an equation for a situation that initially has no energy in the system and then has energy entering the system. For example, within a system there is a motionless car and the ground it is on. Then a person enters the system and pushes the car into motion. With an LOL chart, the initial moment of the situation would have no energy. The system would have the car, the ground and an arrow with a person with full energy bars (this is all qualitative) coming into the system. Lastly, the final moment of the situation would have full energy bars in the kinetic energy category. Comparing the initial and final moments of the situation, I would write the energy equation as 0=Ek. However, this does not make sense. Nothing cannot equal to energy. Under these circumstances, how would I write an equation for this situation? Looking on the positive side, aspects of energy that I do understand are making LOL charts, understand details of a situation and how they affect the energy transfer, and thinking my way through the kinematic equations. Although I feel more confident in these areas, I still think I might have made some mistakes on these topics on the test. As of now, I will continue reviewing energy while waiting for my results on the test.

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