All physics Grade 11 definitions

Definitions

Vector

A physical quantity with magnitude and direction

Scalar

A physical quantity with magnitude only

Vector resolution

To break a vector up into it’s components.

Equilibrium

The state or condition of a system at which all the forces acting on the system produce a zero resultant

Static equilibrium

The state of a system at which all the forces acting on the system produce a zero resultant and the system is at rest

Dynamic equilibrium

The state or condition of a system at which all the forces acting on the system produce a zero resultant and there in no change in the motion of the system.

Weight

Gravitational force the earth exerts on any object on or near its surface

Normal force

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

Frictional force

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

Static frictional force

is the force that opposed the tendency of motion of a stationary object relative to a surface

Kinetic frictional force

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

Newton’s first law of motion

states that a body will remain in its state or move at constant velocity unless a non zero resultant force acts on it

Inertia

The property of a body which causes it to resist a change in its state of rest or uniform motion.

Newton’s second law of motion

When a resultant force acts on an object, the object will accelerate in the direction of the net force. The 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 in the opposite direction

Universal law of gravitation

states that every particle in the universe attracts every other particle 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

Principle of charge quantisation

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 conplete polar separation of positive and negative electric charge in a system

Couloumbs law

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

Electric field

region in space in such electric charge experienced a force.

Electric field at a point

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

Potential difference

It is the energy transferred per unit charge flowing between two points through a conductor.

Emf

It is 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 conductor is directly proportional to the current in the conductor at constant temperature.

Power

It is the rate at which work is done.

Electromagnetic Induction

is the production of an electromotive force (emf) across an electrical conductor in a changing magnetic field.

Faradays Law

states that the emf induced in a coil is directly proportional to the rate of change of magnetic flux linkage.

Lenz’ Law

states that induced current will flow in a direction so as to set up a magnetic field to oppose

the change in magnetic flux.