G484 Definitions Flashcards
Essential definitions and physical laws you must be able to remember for the G484 Unit
Newton’s 1st Law
An object will remain at rest or keep travelling at a constant velocity unless it is acted on by an external force.
Newton’s 2nd Law
The net force acting on an object is equal to the rate of change of momentum. The net force and the change in momentum are in the same direction.
Newton’s 3rd Law
When two bodies interact they exert equal and opposite forces of the same kind on each other.
Linear Momentum
The product of an objects mass and its velocity.
Net Force
The resultant of all the forces acting on an object.
Impulse of a Force
The product of a force and the time for which it acts.
Conservation of Momentum
In a closed system, when bodies interact, the total momentum in any specified direction remains the same.
Perfectly Elastic Collision
A collision in which kinetic energy is conserved (momentum and total energy always conserved).
Inelastic Collision
A collision in which kinetic energy is not conserved (momentum and total energy are conserved).
Radian
The angle subtended at the centre of a circle when the arc length is equal to the radius. Pi radians equals 180 degrees.
Gravitational Field Strength
The gravitational force per unit mass.
Newton’s Law of Gravitation
Any two point masses attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of their separation.
Period
The time taken by an object to complete one orbit or for one complete oscillation by a vibrating object.
Geostationary Orbit
The orbit of a satellite which has a period of one day and is in the equatorial plane.
Simple Harmonic Motion
Motion of an oscillator where acceleration is directly proportional to the displacement and is directed towards the equilibrium position.
Displacement (in terms of shm)
Distance from the equilibrium position, can be positive or negative.
Amplitude
Magnitude of the maximum displacement from the equilibrium position.
Frequency
The number of oscillations per unit time.
Angular Frequency
The rate of change of an angle expressed in radians per second.
Phase Difference
The fraction of an oscillation between the vibrations of two oscillating particles, expressed in degrees or radians.
Pressure
Force per unit area
Internal Energy
The sum of the random distribution of kinetic and potential energies of all the atoms/molecules in a system.
Absolute Zero
The temperature at which a system has minimum internal energy: equivalent to -273.15oC
Specific Heat Capacity
The energy required per unit mass of a substance to raise its temperature by 1K.
Boyle’s Law
The pressure exerted by a fixed mass of gas is inversely proportional to its volume, provided the temperature of the gas remains constant.
Kepler’s 3rd Law
The period of a planet orbiting the Sun squared is proportional to the mean radius cubed.
Kinetic Theory of Gases Assumptions
A gas consists of a large number of particles in rapid, random motion.
All collisions are perfectly elastic.
There are no gravitational forces.
No intermolecular forces exist except during collisions.
The volume of the particles is negligible compared to the volume of the container.
