An example of conservative force is the gravitational force of attraction between the Sun and the Earth. Unlike a conservative force, a non-conservative force is one in which the work depends on the path taken from initial to final positions. It does not follow the law of conservation of energy. There is energy loss, primarily as heat, as the path progresses. The total mechanical energy in the final position is not the same as in the initial position. An example of a non-conservative force is the friction between the wheel and the road during driving.
Conservative vs. Non-conservative Forces
Conservative and Non-conservative Forces: Types and Examples
Work Done by a Conservative Force
- Spring Force: Example – The force with which a spring balance weighs fruits.
- Electrostatic Force: Example – The force that holds the electrons in an atom.
- Magnetic Force: Example – The force with which a bar magnet pulls iron nails.
Non-conservative Force Types
- Friction: Example – The force resisting a box sliding on a floor.
- Air resistance: Example – The resistance offered by air when a ball falls through it.
- Fluid Friction: Example – The resistance offered by water to a submarine.
- Viscosity: Example – Spreading honey over bread. Suppose an object of mass m is lifted to a height h from the surface of the Earth. Then, the potential energies are: At ground: PE1 = 0 At a height above the surface: PE2 = mgh Therefore, the work done W is given by the change in potential energy. W = PE2 – PE1 = mgh – 0 = mgh
