Physics Paper 2 Grade 11 Mock Definitions

Acceleration

The rate of change of velocity.

Average Speed

The total distance travelled divided by the total time taken. It is a scalar quantity.

Average Velocity

The total displacement divided by the total time taken. It is a vector quantity.

Instantaneous Acceleration

The acceleration at a specific moment in time.

Projectile Motion

The motion of an object thrown or projected into the air, subject only to the acceleration of gravity.

Terminal Velocity

The constant speed an object reaches when the drag force equals the gravitational force acting on it.

Reference Frame

A coordinate system that allows us to measure the position, velocity, and time of events.

Inertial Reference Frame

A reference frame in which Newton's first law holds true.

Non-Inertial Reference Frame

A reference frame that is accelerating.

Scalar Quantity

A quantity that has magnitude only and no direction.

Vector Quantity

A quantity that has both magnitude and direction.

Momentum

A measure of how difficult it is to stop a moving object. It depends on the object's mass and velocity.

Impulse

The effect of a force applied over a period of time that changes an object's momentum.

Impulse-Momentum Theorem

The impulse acting on an object is equal to the change in its momentum.

Law of Conservation of Momentum

The total momentum of an isolated system remains constant if no external forces act on it.

Inertia

The tendency of an object to resist changes in its state of motion.

Newton's First Law of Motion

An object at rest stays at rest, and an object in motion stays in motion at a constant velocity, unless acted upon by a net external force.

Newton's Second Law of Motion

The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

Newton's Third Law of Motion

For every action, there is an equal and opposite reaction.

Contact Forces

Forces that arise due to direct physical interaction between two objects.

Friction

A force that opposes the motion of an object.

Drag Force

A resistive force that acts opposite to the direction of an object's motion through a fluid such as air or water.

Air Drag

A resistive force that acts on objects moving through air.

Centripetal Force

A force that acts on a body moving in a circular path and is directed towards the centre around which the body is moving.

Collision

An interaction where two or more objects exert forces on each other for a short time.

Elastic Collision

A collision in which both momentum and kinetic energy are conserved.

Inelastic Collision

A collision in which momentum is conserved but kinetic energy is not conserved.

Perfectly Inelastic Collision

A collision in which the colliding objects stick together and move as one mass after the collision.

Translation Equilibrium

A state in which the sum of all external forces acting on an object is zero.

Work

The product of the force applied to an object, the displacement of the object, and the cosine of the angle between the force and the displacement.

Power

The rate at which energy is transferred or converted.

Mechanical Energy

The sum of an object's kinetic energy and potential energy.

Potential Energy

Energy stored in an object due to its position or configuration.

Gravitational Potential Energy

The energy stored due to the position of an object in a gravitational field.

Elastic Potential Energy

The energy stored in an elastic object when it is stretched or compressed.

Efficiency

A measure of how effectively a system converts input energy into useful output energy.

Conservation of Mechanical Energy

In an isolated system, the total mechanical energy remains constant.

Work-Energy Theorem

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

Conduction

The transfer of thermal energy through a material without the movement of the material itself.

Convection

The transfer of thermal energy through the bulk movement of fluid particles.

Radiation

The transfer of thermal energy away from a body by electromagnetic waves, without the need for a material medium.

Specific Heat Capacity

The energy required to raise the temperature of 1 kilogram of a substance by 1 kelvin.

Specific Latent Heat

The energy required to change the phase of 1 kilogram of a substance at constant temperature.

Black Body

An idealised object that absorbs all radiation falling on it and emits radiation according to its temperature.

Emissivity

A measure of how efficiently a surface radiates energy compared to an ideal black body.

Electromagnetic Waves

Waves composed of oscillating electric and magnetic fields that are perpendicular to each other and to the direction of propagation.

Energy Density

The amount of energy stored per unit volume or mass of a substance.

Solar Constant

The average intensity of solar radiation received at the top of Earth's atmosphere.

Resonance

The phenomenon that occurs when the frequency of incoming infrared radiation matches the natural frequency of a molecule's vibrational or rotational modes.

Pressure

The force applied per unit area.

Density

The amount of mass contained in a given volume.

Mole

The amount of substance containing as many particles as there are atoms in 12 grams of carbon-12.

Ideal Gas Law

The equation of state of a hypothetical ideal gas that relates pressure, volume, temperature, and amount of substance.

Internal Energy

The sum of the kinetic energy and potential energy of the particles that make up a substance.

First Law of Thermodynamics

The total energy of an isolated system remains constant.

Second Law of Thermodynamics

In any natural process, the total entropy of an isolated system always increases or remains constant in ideal reversible processes.

Entropy

A measure of the disorder or randomness in a system.

Carnot Cycle

An idealised model of a heat engine that achieves the maximum possible efficiency for given reservoir temperatures.

Carnot Efficiency

The maximum possible efficiency of a heat engine operating between a hot reservoir and a cold reservoir.

Reversible Process

An idealised process that can be reversed without leaving any net change.

Irreversible Process

A real-world process that cannot be undone without leaving a net change.

Electric Circuit

A system in which electric charge flows through a closed loop.

Electric Current

The rate at which electric charge flows through a conductor.

Electric Potential Difference (Voltage)

The energy per unit charge required to move a charge between two points.

Electromotive Force (EMF)

The work done per unit charge to move a charge completely around a circuit.

Resistance

A measure of how much a material opposes the flow of electric current.

Resistivity

A material property that quantifies how strongly a material resists the flow of electric current.

Ohm's Law

The current through a conductor is directly proportional to the potential difference across it, provided the temperature remains constant.

Internal Resistance

The resistance within the battery itself.

Power in a Circuit

The rate at which energy is transferred in a circuit component.

Series Circuit

A circuit in which resistors are connected end-to-end, forming a single path for current.

Parallel Circuit

A circuit in which resistors are connected across the same two points, providing multiple paths for current.

Variable Resistor

A component that allows the resistance in a circuit to be adjusted.

Potentiometer

A three-terminal resistor with a sliding contact that forms an adjustable voltage divider.

Thermistor

A resistor whose resistance changes with temperature.

Light-Dependent Resistor (LDR)

A resistor whose resistance decreases as the intensity of light falling on it increases.