Physics EOY thing Flashcards
If a question talks about pressure and volume, what formula will you most likely have to use?
Boyles Law - P1V1 = P2V2
What is friction
friction is a force between two objects moving while in contact with each other, with acts to slow down the motion. It converts KE to heat energy
How do you calculate work done by a force?
Force(N) x distance moved (m)
What formula would you use if you wanted to work out how much energy something gains by being heated?
Energy = mass x SHC x temp change
How would you work out SHC?
SHC = energy in joules/mass x temp change
What are the main heat transfers?
Conduction, convection, radiation, insulation
WHat is the best absorber of radiation
matte black
What is the worst absorber of radtion
shiny silver
What is heat energy?
the total kinetic energy of random thermal motion of all the particles in an object
What is the formula for density?
density= mass(g or kg)/volume(cm3 or m3)
What does internal energy equal?
internal energy = kinetic energy + potential energy
WHat happens when a substance is changing state from solid to liquid?
The bonds between the partciles are breaking. this takes energy from the heat source and so the temperature stops going up until all the bonds are broken
What happens when a substance is changing state from gas to liquid?
Bonds are being formed, which releases energy and so it keeps the temperature constant until all the new bonds are formed
If it involves a change of state, what formula are you most likely to use?
energy = mass x specific latent heat
When does Boyle’s Law work?
It only tells us the relationship between the pressure and volume at a CONSTANT temperature?
What does kinetic energy/ gravitational potential energy equal?
0.5mv2
what is temperature?
a measure of the average kinetic energy in particles in a substance
what is specific heat capacity?
Specific heat capacity is the amount of energy required to raise the temperature of 1 kg of a substance by 1 °C.
The student turns on the balance and they read -0.23 g before the metal cube is added.
State the name of this sort of error.
zero error
how does convection work?
As a fluid is heated the particles gain kinetic energy and spread further apart.
This causes the fluid to become less dense and so it will rise above any cooler fluid that hasn’t been heated (because that fluid is more dense).
As the fluid cools down it will become more dense again, and so sink back down.
If this process takes place in a limited space, like a container or a room, it can create a convection current.
what is specific latent heat?
The specific latent heat is the
energy required to change 1kg of a particular substance from one state to another, without
a change in temperature.
how does conduction work?
As one end of a solid object is heated, energy is transferred to the kinetic energy stores of the particles in that end.
This causes the particles to vibrate faster, and so they collide with their neighbouring particles more often.
As the collisions transfer kinetic energy, their neighbours also vibrate faster and collide more often with their neighbours.
This process repeats over and over again so that energy is effectively passed along the object from one particle to the next.
Even though it’s kinetic energy that’s being passed between particles, when considering the object as a whole we say that it’s heat (or thermal energy) that’s being transferred.
We call this overall process of transferring heat energy ‘conduction’.
where can convection take place in?
liquids and gases
how do we calculate the density of a solid experimentally?
Measure the mass of the solid using a balance.
If the shape is regular, measure the volume of the solid using geometry.
If the shape is irregular, measure the volume of the solid by adding it to a Eureka can filled with water. This will cause a volume of water exactly equal to the volume of the solid to flow into the measuring cylinder.
Use the formula to calculate the density of the solid from the mass and volume measurements.
