GCSE Physics (AQA)

346 videos | 23 hours

Energy Energy changes in a system, and the ways energy is stored before and after such changes

Forces & Work

4:55 Energy, Systems and How to Transfer Energy
Spec 4.1.1.1
Previous Heat Flow Next Work Done by a Current
  • A force is a push or pull action on an object.
  • Examples of forces include pushing a box (pushing force from the hand), accelerating a car (driving force from the engine), and lifting a weight (lifting force from the arms).
  • Forces can cause objects to move, stop moving, change shape, speed, or direction.
  • The effects of forces include moving a box across a surface, speeding up a car, and lifting a weight.
  • Forces affect energy stores by transferring energy through work, which is the movement of an object by a force.
  • Work is calculated as the force multiplied by the distance moved in the direction of the force (W = F �� s).
  • Units of measurement: force in Newtons (N), distance in meters (m), and work in joules (J).
  • One joule is the work done when a one Newton force moves an object one meter.
  • Example calculation: A 5 Newton force pushing a box 12 meters on a smooth table results in 60 joules of work.
  • Energy transfers caused by forces typically result in an object gaining kinetic energy, such as transferring kinetic energy from a tennis racket to a ball.
  • When a force acts in the opposite direction of an object���s motion, it usually results in the loss of kinetic energy, such as friction against a car converting kinetic energy to thermal energy.
  • Work done against a force, like gravity when throwing a ball upwards, transfers kinetic energy to gravitational potential energy until the ball stops and begins to fall.

Please subscribe to access these revision notes.

This, and all other video notes, are included in our premium subscriptions.

Premium accounts get access to all videos and revision notes.