year 9 end of years Flashcards
what is the gravitational potential energy equation?
gpe=mgh (mass x gravitational field strength x height
what is the kinetic energy equation?
ke=1/2mv^2 (1/2 or 0.5 x mass x velocity squared)
what is the equation for power?
power=energy transferred/time taken
in the power equation (power=energy transferred/time taken), what are the units?
power = watts, energy transferred = joules - J, time taken = seconds - s
in the gpe equation (gpe=mgh), what are the units?
gpe = joules J, mass = kg, gravitational field strength = N - 10N on earth, height = m
in the kinetic equation (ke=1/2mv^2), what are the units?
ke = J, mass = kg, speed = m/s
what is the work done equation?
w=fd (work done = force x distance moved in the direction of force
in the work done equation (w=fd), what are the units?
w=J, f=N, distance=m
what is the efficiency equation?
efficiency = useful energy out/total energy in
in sankey diagrams, what is put on the top?
useful energy (it goes in an arrow to the right)
in sankey diagrams, what is put on the bottom, angling downwards?
wasted energy (it curves down)
what is the speed equation?
distance / time
what are the units for the speed equation?
speed - m/s, distance - m, time - seconds
what is the refractive index equation?
sin i / sin r
what is the other refractive index equation?
1 / sin c
what is total internal refraction?
when the light bounces back
what type of energy does something moving have?
kinetic energy
is it true that the colder an object is, the more thermal energy it has?
no, it is: the hotter an object is, the more thermal energy it has
what is electrostatic energy?
when 2 charges attract or repel each other
what is magnetic energy?
when 2 magnets attract or repel each other
can energy be created or destroyed?
no
in transverse waves, what direction are the vibrations in?
90* to the direction energy is transferred
in longitudinal waves, what direction are the vibrations in?
the same direction as the wave transfers energy
what are rarefactions?
when waves are further apart
what are compressions?
when waves are closer together
what type of wave (transverse or longitudinal) are most waves?
transverse
what is the sentence to remember the electromagnetic waves?
Rude Men In Venice Use Xray Goggles
what are the 7 electromagnetic waves?
- radio waves
- micro-waves
- infrared
- visible light
- ultra-violet
- x-rays
- gamma rays
do radio waves have a longer or shorter wavelength than the other EM waves?
longer wavelength
do gamma rays have a higher or lower frequency than the other EM waves?
higher frequency
what is refraction?
the change in direction of a wave as it moves from one medium to another
is this true: as the angle of incidence increases, the angle of reflection increases?
yes
does i=r?
yes
why does refraction occur?
because there is a change in wavespeed
