Forces that CAN do work:
* Net Force: Any force that causes a change in an object's motion (acceleration) can do work. This is the most general concept.
* Conservative Forces: These forces have the special property that the work done by them is independent of the path taken. They are also associated with potential energy.
* Gravity: The force of attraction between objects with mass. Think of a ball falling from a height.
* Elastic Force: The force exerted by a spring or other elastic material when deformed. Imagine pulling back a stretched rubber band.
* Electrostatic Force: The force between charged particles. Consider the work done moving an electron in an electric field.
* Non-Conservative Forces: These forces do depend on the path taken. They often involve energy dissipation, like heat or friction.
* Friction: A force that opposes motion between surfaces in contact. Pushing a box across a rough floor.
* Air Resistance: A force that opposes motion through air. A skydiver falling.
* Tension: The force transmitted through a string, rope, or cable when pulled taut. Pulling a wagon with a rope.
* Normal Force: A contact force that acts perpendicular to a surface. Pushing a book against a wall.
* Applied Force: A force applied directly to an object by a person or another object. Pushing a door open.
Key Points:
* Work is done when a force causes displacement. If a force acts on an object but doesn't cause it to move, no work is done.
* Work is a scalar quantity: It has magnitude but no direction.
* Work is measured in joules (J).
Example:
Imagine lifting a heavy box. You exert an upward force, and the box moves upward. You have done work against gravity.
