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Flashcards in Yr9 Energy Deck (17):

What is energy

Energy lets us do work and is required to make anything happen.


Why is energy needed?

Energy is needed to make things move or change.


Can objects have many types of energy?

Yes, eg: The sun.


What are the main forms of energy?

Potential: gravitational, elastic, nuclear, magnetic and chemical.
Active: kinetic, heat, sound, light and electrical.


What is the Law of Conservation of Energy?

Energy cannot be created or destroyed, only transferred and transformed.


What unit is energy measured in?

Kilo joules(kJ) * 1000 J.


Is energy transformations perfect?

No, all energy transformations aren't perfect. Eg: light bulb.


What is efficiency and how do you calculate it?

Efficiency is how much of the total energy is useful. The equation is useful energy, divided by the total energy, times 100.


What are the three types of heat transfer?

Conduction(direct contact), convention(liquids and gasses) and radiation(electromagnetic waves).


What is the difference between conductors and insulators?

Conductors conduct heat well, insulators don't.


What types of renewable energy is there?

Solar, wind, hydro power and biomass.


What is active and potential energy?

Active energy is energy that causes movement of object, particles and waves. Potential energy is stored energy that can be turned into active energy.


What is Ep mean and how do you calculate it?

Ep is calculating gravitational potential energy. It is Ep = mgh. M = mass, G = gravity(10) and H = Height.


What is input and output energy?

Input energy is used by an object. Output energy is given by an object.


Distinguish between active and potential energy.

Active energy can be measured and detected because of the particles, waves and objects that move. Potential energy is stored energy and can become active energy. Example: a pen being lifted up has gravitational potential energy and a pen being dropped has kinetic energy (active).


Describe the energy used and produced by everyday objects.

Light bulbs use electrical energy as an input and transform it into light(useful) and heat(waste). Solar panels absorb sunlight and produce electricity(output).


Describe energy transformations occurring in everyday objects.

A car uses petrol as an energy input. Petrol is a chemical energy, it transforms this chemical energy into kinetic and heat energy. The heat energy is waste and the kinetic is useful because it causes movement.