Define work. What do you mean by work done by a force and work done against a force ? Give examples of each.
Work is the energy transferred when a force causes an object to move.
Work done by a force: When a force applied to an object causes it to move in the same direction as the force, work is done by the force. Example: Pushing a car forward.
Work done against a force: When a force opposes the motion of an object, work is done against the force. Example: Lifting a heavy weight against gravity.