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**Potential energy** is the energy of a particle or system of particles derived from position, or condition, rather than motion. Examples include a stretched spring, raised weight, or charged battery.

**Kinetic Energy** is energy associated with the motion of an object.

In pole vault, the athlete begins by creating as much kinetic energy as possible on the runway. The faster she moves, the more kinetic energy she has, and the higher the possible jump. The pole is constructed of elastic materials such as bamboo and carbon complex. As the athlete plants the pole, the pole begins to bend, absorbing and storing some of the athlete's kinetic energy like a stretched elastic band. The pole straightens out, releasing its stored energy and assisting the athlete upwards against gravity. At the top of her jump, when she has stopped moving upwards, the athlete has her maximum storage of energy. We know the athlete's kinetic energy was stored, not destroyed or used up, because she immediately starts falling on the other side. The closer she gets to the ground, the less potential energy she has. As she falls faster and faster, kinetic energy increases.

A weight lifter lifts a 120 kg mass from the floor to a position above his head, 2.5 meters above the floor. What is the potential energy expressed by the weight?

*Answer:* Using the formula W = mgh, find work, which in this situation equals potential energy.

W = mgh

W = (120)(9.8)(2.5)

W = 2940 J

The potential energy of the weight is 2940 J.

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