BRAINCAKEWork, Energy and Power
Revision notes for Work, Energy and Power in AQA Physics (7407). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- Principle of Conservation of EnergyEnergy is the capacity to do work.
- Work DoneWork is a form of energy.
- Force-Distance GraphsIf a force F acts on an object and it moves a disatcen of s in the direction of the force, the work done on the object by the force W = Fs.
- Kinetic EnergyKinetic Energy is the energy of an object due to its motion.
- Gravitational Potential EnergyGravitational potential energy is the energy of an object due to its position in the Earth's gravitational field work done to raise object = force ×…
- Gravitational-Kinetic Energy TransfersEnergy can be transferred by work done or by heating.
- PendulumA pendulum is an object that is suspended on a string and can swing freely from one side to another.
- Fairground RideThe vehicle on a fairground ride on a downward track is initially at rest at the top of the track with zero kinetic energy.
- PowerPower is defined as the rate of energy transfer.
- Muscle PowerIf walking up a 10m flight of steps takes 12s a person weighing 480N will have leg muscle power of (480 × 10) &div 12 watts.
- Electrical PowerElectrical Power = V I so power = potential difference × current. so electrical energy is E = V I t potential difference x current × time (because…
- Engine PowerThe power supplied by a car engine is known as engine power or motive power.
- Drag ForceResistive forces include friction, air resistance and drag forces.
- Machines and WorkA machine that moves an object does work on the object by applying a force on the object and moving it in the direction of the force.
- Electric MotorAn electric motor exerts a force of 125N on an object causing it to move horizontally at a constant speed of 0.4ms-1.
- Pulley SystemA pulley system can be used to raise a load.
- Efficiencyuseful energy = energy transferred for a purpose Energy is wasted because not all the energy supplied is transferred for the intended purpose.
- Improving EfficiencyIn any process where energy is transferred for a use, some energy is always wasted usually as heat and sound.
- Renewable Energy - Wind PowerA wind turbine is an electricity generator on a tall tower driven by large blades pushed around by the force of thew ind.
- Renewable Energy - Water PowerHydroelectric and tidal power stations make use of the gravitational potential energy transferred when water flows downhill.
- Renewable Energy - Solar PowerThe incident solar energy at the Earth's surface can vary but can reach about 1700W in the summer.