physics keywords Flashcards
what does oscillation mean?
vibrations
define wavelength
distance from one point on a wave to the same point on the next wave
Define amplitude
distance from rest point line to the peak or the trough
define frequency
the number of waves per second
define a transverse wave
a wave vibrating 90 degrees from energy transfer
define a longitudinal wave
a wave vibrating parallel to energy transfer
define velocity
speed in a particular direction
define echo
reflected sound wave
what is the units for wavelength ?
meters (m)
what is the units for frequency ?
Hertz (Hz)
how do find out the wave velocity ?
wave velocity = frequency x wavelength
what is a wave ?
transfer of energy
define compression
vibration close together ( longitudinal)
define rarefaction
vibrations far apart ( longitudinal)
what type of wave is an EM wave?
transverse
how do you find out the wavelength
wavelength = wave velocity / frequency
how do you find out the frequency
frequency =wave velocity / wavelength
define independent variable
the variable you investigate ( i am going to change this & see what happens to my results)
define dependent variable
the factor that is going to be my result. this is the factor i am measuring to collect my data
define control variable
any factor that may effect the results, so i need to keep it the same ,if i don’t my data will be wrong
how do you find percentage change
(difference /original) x 100
what is the equation for speed ?
speed = distance/ time
what is the equation for the time taken ?
time =distance/ speed
what is the equation for distance ?
distance =speed x time
what are EM waves ?
waves that travel through a vacuum of space
name each EM wave in decreasing order
Gamma rays, X-rays,ultra violet waves,viable light waves ,infrared waves,microwaves , radio waves
define accuracy
considered accurate if it is judged to be close to the true value
define precise
measurement are ones in which there is very little spread about the mean value
how can you implicate radio-waves
communication
how can you implicate microwaves
mobile phones communication and cooking food
how can you implicate infrared waves
remote controls and infrared cameras
how can you implicate visible light waves
photography and traffic lights
how can you implicate ultra violate waves
tanning beds, sterilize food and medical instruments
how can you implicate x-rays
medical imaging and airport security
how can you implicate gamma rays
medical treatment
dangers of gamma rays
damage cells causing mutation cell death
dangers of x-rays
to much can lead to cancerous calls
dangers of ultra violet waves
damage eyes,skin cells and skin cancer
dangers of visible light
damage the retina of the eye but normally not dangerous
dangers of infrared
causes skin to burn. prolonged exposure can cause eye damage
dangers of microwaves
causes internal heating of body tissue
dangers of radiowaves
heating of body tissue and increase body temp
what is the equation voltage
voltage=current x resistance
(V=IR)
define scalar quantity
a quantity that has size (magnitude) but no direction
define vector quantity
a quantity that has both size and direction
define mass
measurement of how many particles are in your body. does not change
what is mass measured in
kilograms (kg)
define weight
the measurement of the pull of gravity on your body.depends on what planet your on
what is weight measured in
Newtons (N)
what is a resultant force ?
a single force that represents all of the forces together
what is the equation for acceleration?
change in velocity / time taken
or force / mass
what is the units for acceleration?
m/s(squared)
factors affecting thinking distance
alcohol, drugs, tiredness and caffeine
factors affecting breaking distance
steepness, friction of road,condition of triers, condition of road, weather, break condition,
factors affecting thinking and braking distance
speed
area of square
= length x length
area of rectangle
= length x width
area of trapezium
=1/2(sum of parallel sides) x height
area of triangle
=1/2 base x height
area of parallelogram
=base x perpendicular height
equation for stopping distance
stopping distance= thinking distance + braking distance
volume of sphere
=4/3 x (pie)r(power of three)
surface area of a sphere
=4(pie)r(squared)
volume of a cube
=L x W x H
surface area of a cube
=6(area)
