zoe asked in Science & MathematicsPhysics · 4 months ago

How do I explain how this test charge can end up with kinetic energy, even though it has only PE as it sits there.?

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  • 4 months ago
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    Electric potential energy is the energy that is needed to move a charge against an electric field. You need more energy to move a charge further in the electric field, but also more energy to move it through a stronger electric field.

    You take the positive particle, and start to pull it off the plate, against the pull of the electric field. It’s hard work, because the electric force is pulling them together. If you let the positive particle go, it would snap back to the negative plate, pulled by the electric force. The energy that you used to move the particle away from the plate is stored in the particle as electrical potential energy. It is the potential that the particle has to move when it’s let go.

    Mechanical energy is the sum of the kinetic energy and potential energy of a system; that is, K+U=constant . A loss of U for a charged particle becomes an increase in its K.

  • 4 months ago

    When released, positive charge is attracted to "-" plate. In that process it gains speed at the expense od PE. By the moment it reaches the negative plate, all of its PE will be converted to KE.

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