Physics Flashcards
Equation for weight
W=mg
Equation for force
F=Ke
Equation for work done
W=Fs
Equation for power
P=E/t
Other equation for power
P=W/t
Equation for gravitational potential energy
Ep = mgh
Equation for Kinetic energy
Ek= m(vsquared)/2
Equation for Elastic potential energy
Ee= k(e squared)/2
Equation for efficiency
efficiency = useful output energy transfer/ total input energy transfer
Other Equation for efficiency
Useful power output/ total power input
What is efficiency
An indication of how much of the energy supplied to a device is transferred as a useful output
What do electrons have a charge of
-1.6 * 10 to the -19 coloumbs
What do protons have a charge of
+1.6 * 10 to the -19 coloumbs
What is current determined by
The potential difference across the components and the resistance of the components
What is the equation for resistance
Resistance = potential difference/ current
What does an ammeter measure
How many coulombs of charge pass a point per second - the current
What does a voltmeter measure
The difference in energy of two points in a circuit - the potential difference, how much energy a coloumb loses or gains
What does the potential measure?
It measures the amount of energy each coloumb of charge has at a particular part in a circuit. We colour code the diagram to show the different energies. How much energy each coloumb of charge has in each part of the cell
Equation for speed
S=d/t
Equation for velocity
Displacement/ time - v=s/t
Equation for acceleration
a= change in velocity/ time
Other Equation for acceleration
(v-u)/t
Average walking speed
1.5m/s
Average running or jogging speed
3m/s
Average Cycling speed
6m/s
What is a force
A push or pull caused by an object interacting with another
What are the two non contact forces
Electromagnetic and weight
What is upthrust
Pushing boat etc upwards in water
What is normal contact force
A force perpendicular to the surface it’s touching
What does lift do
Lifts plane in air, pushes it up
Thrust/ drive what does it do
Kelps plane gojng in air , forwards
Drag, air resistance what does it do
Drags plane backwards, slows it down
Tension what is it
Being pulled on a string
what is the difference between mass and weight?
mass is how matter makes up an object, whereas weight is the force of gravity pulling down on an object
what is hooke’s law
the extension of a spring is directly proportional to the force applied provided the limit of proportionality is not exceeded!!!
what is the other euqation of force (hint acceleration)
F=ma
equation of specific heat capacity
E = mc(change in)t
euqation of specific latent heat
E= ml
what two things happen if an object is elastically deformed?
when the force is removed it returns to its initial shape and length/size
what is it called if an object does not return back to its original shape and length when the force is removed?
inelastic deformation
what are the 8 energy stores?
gravitational, nuclear, kinetic, thermal, elastic, electromagnetic, chemical, vibration
what 4 different pathways can energy move between
mechanical working, electrical working, heating by particles and heating by radiation
what are examples of the 4 energy pathways? xx
mechanical - force, electrical -circuit, heating by particles - conduction and convection, heating by radiation - light and infrared
what is the definition of work done?
a measure of how much energy is trasnferred by mechanical working
equation for v squared
v squared = u squared + 2as
what is the definition of power???
the rate at which energy is transferred
if an object is dropped from a certain height to the ground what store does the energy go from to to?
gravitational potential store —> kinetic store
if an object is dropped from a certain height to the ground how woukd you work out the velocity og the coin, given the initial energy from gpe was 9.31J
input it into the equation Ek = 1/2 mvsquared, and work out that it is travelling at 86m/s
if we ignore ? resistance, the energy of one ? is the same as the one it is ? to
air, store, transferred
what are the two types of electric charge, and what happens when the two types are very close to each other?
positive and negative, and they attract and stick together almost
when ? insulators are rubbed together, ? charged electrons move from one ? to the other : eg - a rod and a cloth - the rod gains a positive charge as the negatively charged ? have moved from the ? to the cloth, giving the rod less electrons and therefore more ? so more positively charged protons, so it is ? charged
two, negatively, insulator, electrons, rod, protons, positively
the ? the potential difference the higher the current, they are ? proportional
higher, directly
the higher the resistance the lower the ?, they are ? proportional
current, indirectly
equation of resistance
potential difference (v)/ current (A)
if an ammeter measured 6A how many coulombs of charge pass a point per second?
6 coloumbs of charge per second
what is the potential difference?
how much energy a coulomb loses or gains, the difference in energy of two points on a circuit
if one point has 3J of energy and one has 1.5J - how many volts does each point have and what is the potential difference?
they have 3V and 1.5V respectively, and the potential difference is the difference between the two so 3-1.5 so 1.5V
having more bulbs in a series circuit ? the current, but in a parallel having more bulbs ? the current since the total ? decreases and it gives the current more ? to and from the cell
decreases, increases, resistance, resistance, paths
what is resistance?
a measure of the opposition to the current flow in an electrical current
by adding an extra wire around a bulb in a series circuit the ammeter reading ? so the ? also increased, but the voltmeter reading ? since there’s no ? flowing through the bulb so very ? potential difference
increases, current, decreases, current, low
