Physics Energy Flashcards
What is the law of conservation of energy?
Energy cannot be created or destroyed , it can only be transferred between different energy stores
What are the different types of stores that energy can be in?
Kinetic (movement) energy store Thermal (heat) energy store Elastic potential energy Magnetic energy store Electrostatic energy store Chemical energy store Gravitational potential energy store
Can energy be transferred from thermal to kinetic energy?
Yes
This transfer fits with the law of conservation of energy (read it)
Info on different energy Stores , see page 97 of the CGP Book.
What is the kinetic energy store?
Anything that moves has energy in its kinetic energy store.
A car
Wills moving legs in football
Info on different energy Stores , see page 97 of the CGP Book.
What is the thermal energy store?
Everything has some heat energy in its thermal energy store
The hotter something is, the higher it’s temperature, and it has more energy in its thermal energy store
Info on different energy Stores , see page 97 of the CGP Book.
What is the elastic potential energy store?
Anything stretched, like a rubber band ready to ping has energy in its elastic energy store
Info on different energy Stores , see page 97 of the CGP Book.
What is the magnetic energy store?
Magnets that attract or repel one another, have energy in their magnetic energy store
Info on different energy Stores , see page 97 of the CGP Book.
What is the chemical energy store?
Anything with energy which can be released by a chemical reaction has chemical energy in its chemical energy store
Food has energy in its chemical energy store, so do cells in your body
Batteries have lots of energy in their chemical energy stores
Info on different energy Stores , see page 97 of the CGP Book.
What is the gravitational potential energy store?
(Need to know this one)
It’s energy a high object has.
Anything in a gravitational field has energy in its gravitational potential energy.
E.g. an apple held high on earth (where there is a gravitational field) has gravitational potential energy.
What is energy transfer about?
It’s movement from one energy store to another energy store.
E.g when an Apple drops to the ground, energy moves from the gravitational potential energy store to the kinetic energy store.
What is the strength of the gravitational field strength on earth?
9.8 Newton’s per kg (N/kg)
What is the equation to calculate the amount of gravitational energy an object has?
Gravitational Potential energy = Mass x gravitational field strength x height
Ep = m x g x h
Units
J (energy)= kg (mass) x N/kg (g) x m (height)
g is gravitational field strength
How do you recognise when energy in the gravitational store is transferred into kinetic energy?
It starts to move
When it has motion it has kinetic energy.
The higher the speed of movement the higher the kinetic energy.
Also objects with a large mass will also have greater kinetic energy
How do you recognise when energy in the kinetic energy store is transferred into potential energy?
If kinetic energy is transferred to gravitational energy, work is done against the force of gravity to hold it up.
When this work (to lift it) is done it is transferred to the object and it gains potential energy
