06. P1 Energy Flashcards
What unit is energy measured in?
Joules
Name five forms of energy.
Heat, Light, Sound, Chemical, GPE, Ek, Elastic, Electrical, Nuclear
What is meant by the conservation of energy?
Total energy into a transfer, must equal the total energy out of the transfer.
What is the equation used to calculate percentage efficiency.
(Useful energy out ÷Total energy in) x100
Why type of energy is stored in a fossil fuel?
Chemical
Why type of energy is stored in food?
Chemical
What is the difference between a filament lamp and an energy saving bulb?
Filament lamp is less efficient, so for the same energy out it uses more electrical energy. Wastes more energy as light.
What is the energy transfer of a petrol motor?
Chemical -> Kinetic + heat + sound
Name three items which use motors.
CD players, washing machines, food processors, games consoles, toothbrush, remote control cars, mobile phones (vibration), hairdrier…….
What does GPE stand for?
Gravitational Potential Energy
Which equation connects GPE and mass?
GPE = m x g x h
What are the units of GPE?
Joules
Name one object which has Elastic Potential Energy stored in it.
stretched elastic band, bow (and arrow), fishing line under tension, wind up toy …..
What type of object has Kinetic Energy?
Any moving object
Which Equation connects Kinetic Energy and Velocity?
Ek = 0.5 x m x v2
If you double the velocity, what happens to the kinetic energy?
Double velocity = quadrupled kinetic energy
What is the energy transfer of a child going down a slide?
GPE -> Kinetic + heat
What are the units of work done?
Joules
What equation can you use to calculate the work done by a force?
Work done = Force x distance
Which Equation connects Power and Energy?
Power = Energy ÷ time or Energy = Power x time
Which unit is Power measured in?
Watts
What can be used in an object in order to reduce friction between moving parts?
Oil or lubrication
How many watts are in 5 Megawatts?
5MW = 5,000,000 W
Hoe many joules are in 2 kilojoules?
2kJ = 2,000 J
How many joules does a 10 watt speaker give out in 1 minute?
E = P x t = 10 x 60 = 600J
What happens to the kinetic energy of an object if you double the objects mass but it remains at the same speed?
If mass doubles, kinetic energy doubles
Friction is a force which acts between two objects moving past each other. What is the effect does friction have on its surroundings?
Friction causes heat wasted to the surroundings (warms the surrounding objects like air etc.)
What is the energy store in a candle?
Chemical
Which store of energy does a moving car have?
Kinetic
What is the change in energy store for a falling object?
Gravitational transfering to Kinetic
