y4 Definitions Flashcards
Velocity formula (waves)
V=f x wavelength
Frequency formula
F=1/T
Pressure formula
P=F/a
Boyles Law
P1V1=P2V2
Speed
Distance travelled per unit time
Velocity
Rate of change of displacement
Acceleration
Rate of change of velocity
Newtons first law
All objects will remain in a state of rest or uniform motion in a straight line unless acted upon by a resultant force
Newtons second law
When a resultant force acts upon an object of constant mass, the onject will accelerate in the direction of the resultant force. The productof mass and acceleration if the object gives the resultant force
Newtons third law
When object A exerts a force on object B, object B will exert an equal amd opposite force on object A
Acceleration due to gravity
Constant rate of change of velocity and the value is 10m/s2
Mass
Amount of matter in a body
Weight
Gravitational force acting on an object
Inertia
The reluctance of a body to change its state of rest or motion due to its mass
Gravitational field
Region in which a mass experiences a force due to gravitational attraction
Gravitational field strength
Gravitational force acting per unit mass
Wave motion
A periodic motion which transfers energy from one place to another without any transfer of matter
Transverse waves
A wave that travels in a direction perpendicular to the direction of the vibration of particles
Longitudinal waves
A wave that travels in a direction parallel to the direction of the vibration of the particles
Wavefront
An imaginary line on a wave that joins all the points which have the same phase of vibration
Frequency
The number of complete waves produced per second
Wavelegnth
The distance between 2 consecutive crests or troughs
SI Unit: m
Period
Time taken to produce one complete wave
Amplitude
Maximum displacement from rest position
SI Unit: m
Pressure
Force acting normally per unit area
Brownian motion
The constant and random motion of heavier suspended particles caused by the uneven collisions of surrounding lighter, fast moving particles in the fluid, causing the heavier particles to move in the direction of the resultant force
Heat capacity
The amount of thermal energy required to change the temperature of an substance by 1C or 1K
Specific heat capacity
The amount of thermal energy required to change the temperature of 1 kg of substance by 1C or 1K
Latent heat
The amount of thermal energy required to change the state of a substance without a change in temperature
Latent heat of vaporisation (specific)
The amount of thermal energy required to change the state of (1kg) of substance from liquid to gaseous or vice versa without a change in temperature
Latent heat of fusion (specific)
The amount of thermal energy required to change (1kg) of a substance from solid state to liquid state or vice versa without a change in temperature
Law of electrostatic
Unlke charges attract and like charges repel
Pressure
Force acting normally per unit area
Pascals Principle (liquids)
Pressure exerted anywhere in a confined liquid is transmitted undiminished in all directions throughout the liquid
Atmospheric pressure
Pressure exerted by the weight of the atmosphere or the pressure at any location on earth caused by the weight of the column of air above it
760mm Hg
Velocity
Speed
Rate of change of displacement/distance
Acceleration
Rate of change of velocity
Phase
any 2 points moving in the same direction and have the same speed and the same displacement from the equilibrium position (any 2 crests or troughs are always in phase)
Compressions
Rarefaction
regions where the medium’s density is higher than the surrounding density
regions where the medium’s density is lower than the surrounding density
Speed (waves)
distance moved by a wave in one second.
Temperature
Measure of the average kinetic energy of the particles that make up a body
Heat
Measure of how much thermal energy is transferred from one body to another
Phase change
change in state of matter without change in temperature
Static electricity
imbalance of electric charges within or on the surface of a material or between materials
law of electrostatic
like charges repel and unlike charges attract
triboelectric series
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Electric field line
path a positive charge would take in an electric field
Current
rate of flow of electric charge through a given cross section of a conductor
emf
across battery
work done by the source in driving a unit charge around a complete circuit
pd
across component
pd of a component in an electric circuit is the work done to drive a unit charge through the component
resistance
resistance of a component is a ratio of the pd across the component to the current flowing through the component
Ohms Law
current passing through a metallic conductor is directly proportional to the pd across it, provided that physical conditions remain constant
Power
rate of dissipation of energy
kWh
1 kWh is the amount of electrical energy used by a 1kW appliance in 1 hour
magnetic field
region surrounding a magnet, in which a body of magnetic material experiences a magnetic force
law of emi
phenomenon of inducing an emf in a circuit by changing the magnetic field
faradays law
magnitude of induced emf in a circuit is directly proportional to the rate of change in magnetic flux in a circuit
lenz law
the direction of induced emf is always such that the magnetic effect opposes the motion or change producing it
conservation of energy law
energy can neither be created or destroyed but it can be changed from one form to another or transferred from one body to another
centre of gravity
point through which the weight of a body acts for any orientation of the body
principles of moments
sum of clockwise moments about a point = sum of anticlockwise moments about a point
moment/torque
turning effect of a force about a pivot is the product of the force and the perpendicular distance from the pivot to the line of action of the force
force
a push or a pulla acting on an object due to its interaction with another object
