revision cards Flashcards
Balanced forces-effect of one force is cancelled out by another
changing motion- body speeding up or slowing down
Unbalanced forces- forces acted on an object not balanced
Force acting in same direction
20+10N
Force acting in opposite direction
20-10N
Contact force- force that act between two objects that are touching
Non contact force- force that acts between two objects that aren’t touching
Physical quantity- something that can be measured
scalar quantities only have magnitude
vector quantities have magnitude and direction
speed= distance divided by time
convert to kilometres by multiplying by 1000
Weight = mass x gravitational field strength
adding and cancelling waves
two waves meet they affect each other called superposition
produce higher wave= amplitude
frequency= more than 20,000 ultrasound
average speed= distanced travelled divided by time taken
We can detect sound using our ears. An ear has an eardrum inside, connected to three small bones. The vibrations in the air make the eardrum vibrate, and these vibrations are passed through the three small bones (called ossicles) to a spiral structure called the cochlea. Signals are passed from the cochlea to the brain through the auditory nerve, and our brain interprets these signals as sound.
Amplitude – maximum height of a wavewavelength- length of a single wave
Frequency- number of waves produced each second
Transverse waves
Microphones convert sound waves into a electrical signal
Soundwaves hit a diaphragm which causes it to move
Magnet is connected
Creates magnetic field around coil
Coil is moving, creates an electrical current
Fluctuation- Rising or falling figure
Oscillations- the repeated and regular oscillations below the same position
Vibrations- repeated movements back and fourth
Oscillations- vibrations
Mechanical waves cause oscillations of particles in a solid, liquid or gas and must have a medium to travel through. Electromagnetic waves cause oscillations in electrical and magnetic fields.
Mechanical waves cause oscillations of particles in a solid, liquid or gas and must have a medium to travel through. Electromagnetic waves cause oscillations in electrical and magnetic fields.
rest position - the undisturbed position of particles or fields when they are not vibrating
displacement - the distance that a certain point in the medium has moved from its rest position
peak - the highest point above the rest position
trough - the lowest point below the rest position
amplitude - the maximum displacement of a point of a wave from its rest position
wavelength - distance covered by a full cycle of the wave, usually measured from peak to peak, or trough to trough
time period - the time taken for a full cycle of the wave, usually measured from peak to peak, or trough to trough
frequency - the number of waves passing a point each second
A real image is an image that can be projected onto a screen
A virtual image appears to come from behind the lens.
convex- object or shape that curves
focal point- the distance between the centre of the lens and the focal point
Cameras and eyes contain convex lenses. For a distant object that is placed more than twice the focal length from the lens, the image is:
inverted
diminished
real
Projectors contain convex lenses. For an object placed between one and two focal lengths from the lens, the image is:
inverted
magnified
real
concave- curving inwards
refracted- deflected from a straight path
diverge- when a light wave splits up or spreads out
the same side of the principal axis, meaning the image will be upright
closer to the principal axis, so the image will be smaller than the object
Parts that protect our eye- eyebrows, eyelashes, eyelids, lachrymal glands
lachrymal glands- help clean the eye
incharge of vision- iris,pupil, eye lense, retina
light enters iris job is to control what light goes into the eye. light gets to the pupil
eyelense- recieves info/ helps you focus
retina- back/ recieves light
optic nerve- carrys info to brain/ comprehend what our eyes can see
