The work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes.
-A rollercoaster going down a hill
-A bursting firecracker
Energy stored in a system of forcefully interacting physical entities.
-A car parked at the top of a hill
-A boulder sitting at the top of a mountain
-Water behind a dam
Conservation of Energy
The total energy of an isolated system cannot change—it is said to be conserved over time. Energy can be neither created nor destroyed, but can change form.
-When a moving car hits a parked car and causes the parked car to move, energy is transferred from the moving car to the parked car.