The energy of an object in a gravitational field (E=mgh)
I can calculate the change in energy of an object because of its movement in a gravitational field.
The energy of an object in a gravitational field (E=mgh)
I can calculate the change in energy of an object because of its movement in a gravitational field.
Lesson details
Key learning points
- When an object moves upwards, work is done against the gravitational force.
- The gravitational force acting on an object does work to speed it up when it is falling.
- Weight = mass x gravitational field strength, W = mg
- Gravitational potential energy of an object = mass × gravitational field strength × height
Common misconception
Pupils often think that the amount of energy in the gravitational store depends on the path taken by an object to change its height, or the speed of an object at a particular height.
Teaching should include examples of objects increasing height by the same amount by different routes, and examples of objects at the same height moving at different speeds.
Keywords
Gravitational store - Objects have energy in the gravitational store because of their mass and their height.
Work done - Work is done whenever a force makes an object move. The amount of work done is equal to the force multiplied by distance moved in the direction of the force.
Weight - Weight = mass × gravitational field strength, measured in newtons.
Gravitational field strength - Gravitational field strength, g, is the force per kilogram caused by a gravitational field.
Gravitational potential energy - The energy stored in an object due to its height above the ground.
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
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