Matric Physics Definitions

Weight

The gravitational force the Earth exerts on any object on or near its surface.

Normal Force

The force or the component of a force which a surface exerts on an object with which it is in contact, and which is perpendicular to the surface.

Frictional Force

The force that opposes the motion of an object and which acts parallel to the surface.

Static frictional force

The force that opposes the tendency of motion of a stationary object relative to a surface.

Kinetic frictional force

The force that opposes the motion of a moving object relative to a surface.

Newton's First Law of Motion:

A body will remain in it’s state of rest or move at constant velocity unless a non-zero, net force acts on it.

Newton's Second Law of Motion

When a non-zero, net force acts on an object, the object will accelerate in the direction of the net force. This acceleration is directly proportional to the force and inversely proportional to the mass of the object.

Newton's Third Law of Motion

When object A exerts a force on object B, then object B exerts a force on object A equal in magnitude but opposite in direction.

Coefficient of Kinetic Friction

The ratio of the kinetic frictional force acting on a moving object and the normal force acting on the object.

Coefficient of Static Friction

The ratio of the static frictional force acting on a stationary object and the normal force acting on the object.

Newton's Law of Universal Gravitation

Each body in the universe attracts every other body with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.

Free fall/ Projectile Motion

The motion of an object under the influence of the force of gravity only.

Projectile

An object that is launched with an initial velocity and upon which the only force acting on it, is the force of gravity.

Momentum

The product of an object's mass and its velocity

Impulse

The product of the net force acting on an object and the time the net force acts on the object

Isolated sytem

A system on which the net external force is zero

Principle of conservation of linear momentum

The total linear momentum of an isolated system is conserved

Elastic Collision

Is a collision in which total kinetic energy is conserved

Inelastic Collision

Collision in which total kinetic energy is not conserved

Conservative Force

a force for which the work done in moving an object between two points is independent of the path taken.

Non-Conservative Force

A force for which the work done in moving an object between two points depends on the path taken

Gravitational Potential Energy

The energy an object has because of its position in the gravitational field relative to a reference point.

Kinetic Energy

The energy an object possesses as a result of its motion

Mechanics energy

The sum of an object's potential and kinetic energies

Principal of conservation of mechanical energy

The total mechanical energy in an isolated system is conserved.

Work-Energy Theorem

The net work done on an object is equal to the change in the object's kinetic energy.

Power

the rate at which work is done

Doppler Effect

The apparent change in frequency (pitch/wavelength) of a sound detected by a listener as a result of the relative motion between the source of the sound and the listener.

Frequency

The number of wave pulses per second.

Pitch

The time taken for one complete wave pulse.

Wavelength

The distance between two successive points in phase

Principle of charge quantization

All charges in the universe consist of an integer multiple of the charge on one electron.

Principle of conservation of charge

The net charge of an isolated system remains constant during any physical process.

Polarisation of charges

The partial or complete polar separation of positive and negative electric charge in a system.

Coulomb's law

The magnitude of the electrostatic force of attraction or repulsion exerted by one point charge on another point charge is directly proportional to the product of the magnitudes of the charges and inversely proportional to the square of the distance between their centres.

Electric field

A region of space in which an electric charge experiences a force.

Electric field at a point

The electrostatic force experienced per unit positive point charge placed at that point.

Potential difference

The energy transferred per unit charge flowing between two points through a conductor.

Emf

The energy provided by a battery per unit charge flowing through the battery.

Terminal potential difference

The voltage measured across the terminals of a battery when charges are flowing in the circuit.

Current strength

The rate of flow of charge.

Resistance

The ratio of the potential difference across a resistor to the current in the resistor.

Internal resistance

The resistance within a battery when current is flowing which causes a decrease in the potential difference that the battery can supply to the external circuit.

One ohm

One ohm is equal to one volt per ampere.

One coulomb

The charge transferred in a conductor in one second if the current is one ampere.

Ohm's law

The potential difference across a resistor is directly proportional to the current in the resistor at constant temperature.

Power

The rate at which work is done

RMS Voltage (Vrms)

The AC potential difference that will produce the same amount of energy as an equivalent DC potential difference

RMS Current (Irms)

The alternating current that will produce the same amount of energy as an equivalent direct current.

Carbon brushes

It takes current into and out of the coil by maintain electrical contact with the slip rings

Split Ring Commutator

It allows for the continuous rotation of the armature in the same direction by reversing the current in each side of the coil every half cycle.

Slip rings

It ensures free rotation of the armature by providing sliding contact between the armature and the carbon brushes.

Photoelectric effect

The process whereby electrons are ejected from a metal surface when light of suitable frequency is incident on that surface.

Photon

An energy packet of light

Threshold frequency

the minimum frequency of light needed to emit electrons from a certain metal surface.

Threshold Wavelength

The maximum wavelength of light needed to emit electrons from a certain metal surface.

Work Function

The minimum energy that an electron of a particular metal needs to be emitted from the metal surface.