Different forms of energy Flashcards
Define mechanical energy
The energy possessed by a body due to its state of rest or motion
In which two forms does mechanical energy exist?
- potential energy
2. kinetic energy
What it the total mechanical energy of a body?
The sum of its potential and kinetic energy
Define potential energy
The energy possessed by a body due to its position or size and shape is called potential energy
Give the symbol of PE
U
Give examples of objects that have PE
- A body placed at a height above the ground
- A wound up watch spring
- A compressed spring
- A bent bow
- A stretched rubber string
Name the two kinds of PE
- gravitational PE due to its changed position
2. elastic potential energy due to its changed size and shape
Define gravitational PE
The PE possessed by a body due to the force of attraction of Earth on it, is called gravitational PE
When is GPE 0?
When a body is at infinity
Why is GPE 0 when a body is at infinity?
Because the force of attraction of Earth on the body is then zero
What is GPE at a point equal to?
To the amount of work done by the force of attraction of Earth in brining that body from infinity to that point
When is GPE negative?
At a finite distance from the earth
Why is GPE of a body negative at a finite distance from the earth?
Since work is done by the force of gravity itself
What happens to the GPE as distance of the body from the surface of Earth increases or decreases?
As distance of body from surface of Earth increases, the force of attraction of Earth decreases and GPE increases
