Physics revision Year 9 Flashcards
Name 11 types of energy
Magnetic, Kinetic, Heat, Light, Gravitational potential, chemical, sound, elastic, electric and nuclear
What measurement do we use for energy?
Joules
Fill in the gaps: As an object falls, its gap energy is turned into gap energy
As an object falls, its gravitational potential energy is turned into kinetic energy
Fill in the gaps: As an object hits an obstacle, it converts its gap energy (as it slows down) into gap energy and gap energy (which dissipate into the surroundings
As an object hits an object, it converts its kinetic energy (as it slows down) into heat and sound energy (which dissipate into the surroundings).
Fill the gaps: As a vehicle accelerates, it converts gap energy (in a fuel/battery) into gap energy (in the brakes)
As a vehicle accelerates, it converts chemical energy (in a fuel/battery) into kinetic energy (as it speeds up)
Fill in the gaps: As a vehicle slows down, gap energy is converted into gap energy (in the brakes)
As a vehicle slows down, kinetic energy is turned into heat energy (in the brakes)
Fill in the gaps: As a kettle boils water, it converts gap energy into gap energy.
As a kettle boils water, it converts electrical energy into heat energy.
How do we calculate kinetic energy?
Kinetic energy=0.5x(speed)^2
How do we calculate gravitational potential energy?
Gravitational potential energy=mass x gravitational field strength x height
How do we calculate power?
Power = work done/time
What is the conservation of energy?
Energy in=energy out. Energy can be transferred usefully, stored or dissipated, but it cannot be created or destroyed.
What is another way to say work done?
Energy transferred
Define power
The rate at which energy is transferred (or the rate at which work is done)
What is power measured in?
Watts (W)
How do we reduce unwanted energy transfers?
Lubricants and thermal insulation
If there is a high thermal conductivity of a material, is there a high or low rate of energy transfer by conduction?
High rate
How do we calculate efficiency?
Efficiency = useful out / total in
Are chemical changes reversible?
No
Are physical changes reversible?
Yes
What is internal energy?
Total kinetic and potential energy of all the particles that make up a system
What is specific heat capacity?
The amount of energy needed to raise the temperature of 1kg of a substance by 1 degrees celsius
When a change of state occurs, does temperature change?
No
What is specific latent heat?
The amount of energy needed to change the state of 1kg of a substance with no change in temperature
What is the specific latent heat of fusion?
The change of state between a solid and liquid
What is the specific latent heat of vaporisation?
The change of state between a liquid and gas
