Definitions G484 Flashcards
Resonance
The build up of a large amplitude oscillation when the frequencies of vibrating objects match
Phase
Whether a substance is a solid, liquid or gas
Ideal gas
A gas that has internal energy only in the form of kinetic energy
Specific latent heat of fusion
The quantity of energy required per unit mass to change a substance from a solid to a liquid at a constant temperature
Displacement
The distance of the body from an equilibrium position
Amplitude
The maximum displacement
Frequency
The number of oscillations per unit time
Angular frequency
The product of 2pif or 2pi/period
Specific latent heat of vapOrisation
The quantity of energy required per unit mass to change a substance at constant temperature from a liquid into a vapour
Ideal gas temperature
For a fixed mass of an ideal gas at constant pressure, it’s volume is proportional to the ideal gas temperature in kelvin.
One mole
The Avogadro constant is the number of particles in one mole.
Boltzmann constant
1.3807*10^-23JK^-1 the gas constant for a single molecule
Boyle’s law
Pressure is inversely proportional to volume for a fixed mass of gas at constant temperature
The Newton
The force which gives a mass of one kg an acceleration of one ms^-1
Gravitational field strength
Force per unit mass at a point in a gravitational field.
Newton’s first law
A body will remain at rest or continue to move with constant velocity unless acted on by a force
Newton’s second law
Force is proportional to the rate of change of momentum
Newton’s third law
When one body exerts a force on another, the other body exerts an equal and opposite force on the first body.
Principle of conservation of linear momentum
Total momentum is constant for a closed system
Inelastic collision
Some loss of kinetic energy during the collision. The coefficient of restitution is less than one.
The kilowatt-hour
The energy used by a 1kW device in 1h
Internal energy
Sum of randomly distributed kinetic energy and potential energy of molecules
Impulse of a force
Force x time for which the force acts. (Change in momentum)
Specific heat capacity
Energy required to raise the temperature of a unit mass of a substance by a unit temperature rise.
Equilibrium
The resultant force is zero.
Simple harmonic motion
Acceleration is proportional to displacement and is directed in the opposite direction to the displacement, towards the equilibrium position.
Thermal equilibrium
No net heat flow between objects
Perfectly elastic collision
A collision with no loss of kinetic energy. Coefficient of restitution = 1
Linear momentum
Mass x velocity
Kepler’s third law
The cube of the planet’s mean radius of its orbit is proportional to the square of the orbital period.
Centripetal acceleration
For an object travelling in a circle of radius r with constant speed v, a is given by a=v^2/r in a direction towards the centre of the circle.
Field
The region in which a force operates
One radian
The angle subtle dead at the centre of a circle by an arc of length equal to the circle’s radius.
Period
For circular motion, the time taken to complete one revolution. v=Circumference/time
Newton’s law of gravitation/ gravitational force
Between two bodies, it’s directly proportional to the product of their masses, and inversely proportional to the square of the distance between them squared.
F=(-GMm)/r^2
Period of a planet
The time taken for one complete orbit of the sun
Damping
Deliberately reducing the amplitude of an oscillation
Impulse
The expression F/\t. It equals the change in momentum of a body. It is the area beneath a force-time graph
