Key Definitions - Circ Motion, SHM, g-fields, E-Fields

Amplitude

The maximum displacement from the equilibrium position

Angular displacement

The angle about a fixed axis described by a rotating or orbiting object in degrees or radians from a fixed point

Capacitance

The charge stored per unit potential difference

Centripetal acceleration

Acceleration towards the centre of a curved or circular path.

Centripetal force

A force causing an object to move in a circle, acting towards the centre of the circle

Coulomb's Law

The force between two point charges separated by a distance r is directly proportional to the product of the charges and inversely proportional to the square of the distance between them

Critically damped

When the resistive forces on a system are just enough to prevent oscillation and the object returns to equilibrium in the minimum possible time

Damping

The removal of energy from an oscillating system.

Dielectric

A material which is an electrical insulator that can be polarised by an applied electric field.

Dielectric constant

The factor by which the electric field between two charges is decreased by the presence of the dielectric, relative to a vacuum

Electric field

A region around a charged particle or object within which a force would be exerted on other charged particles or objects.

Electric Field Strength

The force per unit charge on a positive test charge placed in the field at that point. A vector quantity.

Electric potential

The work done per unit charge in bringing a small positive test charge from infinity to a specific point.

Electric potential difference

The work done per unit charge moving the charge between two points.

Equipotential surface

A surface where the potential is the same everywhere. No work is done against field or by field when object is moved along this surface

Forced oscillation

An oscillation imposed upon a body or system by an external energy source

Free oscillation

An oscillation in which a body or system oscillates at its natural frequency

Geostationary Orbit

Orbit in which a satellite moves in the same direction as the Earth's rotation, above the equator, with an orbital period of 24 hours

Gravitational Field Strength

The attractive gravitational force per unit mass at a specific point in a gravitational field

Gravitational potential

The work done per unit mass by the gravitational field to move a mass from infinity to a specific point.

Gravitational potential difference

The change in energy, per kg, of a body of mass caused by a change in position within a gravitational field

Gravitational Field

A region of space in which an object with mass experiences a force

Mechanical Oscillation

A periodic conversion of energy such as from potential energy to kinetic energy to potential energy.

Newton's law of universal gravitation

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 the distance between them

Polar orbit

An orbit in which a satellite passes over both the North and South poles of the Earth.

Radial field

A field in which the field lines are straight and either converge or diverge from a single point

Resonance

Large amplitude vibrations caused when the driving frequency matches the natural frequency of a system

Resonant frequency

The natural frequency at which an object or system oscillates

Simple harmonic motion

The periodic motion in which the restoring force (and thus acceleration) is proportional to the displacement and acts in the opposite direction

Synchronous orbit

An orbit in which an orbiting body has an orbital period equal to the rotational period of the body it orbits, in the same direction of rotation as that body.