Energy And Efficiency Flashcards
What form of energy does a compressed spring have?
Elastic potential energy
What happens when an object falls and gains speed?
It’s gravitational potential energy decreases and it’s kinetic energy increases.
Where does the chemical energy stored in your muscles come from?
From the food that you eat
It is not possible to create or destroy energy. What is it possible to do?
To transfer energy from one form to another or one place to another
What is the conservation of energy?
It means that the total amount of energy is always the same. And this applies to all energy transfers.
What is transferred in a solar cell?
Light energy is transferred to electrical energy.
In terms of energy what happens when you burn a fuel?
Chemical energy in the fuel is transferred to the surrounding which get warmer.
What energy transfers take place when you turn on a torch?
Chemical to electrical to light and transfer by heating.
What does a swinging pendulum transfer?
It transfers energy from gravitational potential energy to kinetic energy and back again as it swings.
Out of a machine what types of energy do we get?
Useful and wasted energy
What is useful and wasted energy?
Useful- transferred to the place we want and in the form we want.
Wasted- not usefully transferred.
Where do both energies go to?
They both end up being transferred to the surroundings which become warmer.
What happens to the wasted energy from a light bulb?
Transferred to surroundings which gets warmer.
Why should we talk about energy being wasted not energy being lost?
Because the law of conservation tells us that energy cannot be destroyed.
Fill I’m:
The ______ energy that is wasted by the machine the more efficient.
Less
What does the efficiency equal?
Useful energy transferred / total energy supplied X 100
In a light bulb for every 25 joules of energy that are supplied to the bulb ,5 joules are usefully transferred into light energy. What is the efficiency of the bulb ?
20%
A machine is adjusted so that it wastes less energy because of friction. What happens to the efficiency of the machine?
It increases
What form of energy does a moving car have?
Kinetic energy
What form of energy does a stretched spring have?
Elastic potential energy
When is electrical energy transferred?
When an electric current flows.
What are the useful energy transfer in a hairdryer?
Electrical to kinetic and energy transferred by heating
What are the useful energy transfers in a television?
Electrical to light and sound
What energy transfers take place when you lift a ball into the air and then drop it so it falls to the ground?
Kinetic to gravitational potential energy to kinetic
