CAIE Physics A-Level: Topics 1–5 Comprehensive Review

Vocabulary practice flashcards covering fundamental physical quantities, kinematics, dynamics, forces, density, pressure, and energy concepts from CAIE Physics A-Level.

Physical Quantity

A feature or property that consists of a numerical magnitude and a unit.

SI Base Units

The fundamental units used alongside the base SI physical quantities: kilogram ($\text{kg}$) for mass, metre ($\text{m}$) for length, second ($\text{s}$) for time, ampere ($\text{A}$) for current, kelvin ($\text{K}$) for temperature, and mole ($\text{mol}$) for amount of substance.

Homogeneous Equation

An equation in which the base SI units on both sides of the equals sign are identical.

Random Error

An error that affects precision by causing measurements to fluctuate and spread unpredictably about the mean value; it cannot be completely eliminated.

Systematic Error

An error that affects accuracy due to faulty apparatus or experimental procedures, causing all recorded values to be consistently too high or too low by the same amount.

Precision

The degree of consistency between repeated measurements, indicated by values that fluctuate slightly about a mean value.

Accuracy

A measure of how close a recorded measurement is to the true value.

Absolute Uncertainty

The uncertainty of a measurement presented as a fixed numerical quantity with appropriate units.

Scalar

A physical quantity that has magnitude only and no direction.

Vector

A physical quantity that possesses both a magnitude and a direction.

Displacement

The overall distance travelled by an object from its starting position in a specified direction.

Velocity

The rate of change of displacement with respect to time ($\frac{\Delta s}{\Delta t}$).

Acceleration

The rate of change of velocity with respect to time ($\frac{\Delta v}{\Delta t}$).

Instantaneous Velocity

The velocity of an object at a specific point in time, found by drawing a tangent to a displacement-time graph and finding its gradient.

Uniform Acceleration Equations

The kinematic formulas applied when acceleration is constant: $v = u + at$, $s = \frac{u + v}{2}t$, $s = ut + \frac{1}{2}at^2$, and $v^2 = u^2 + 2as$.

Newton's First Law of Motion

An object will remain at rest or continue travelling at a constant velocity unless it experiences a resultant force.

Newton's Second Law of Motion

The resultant force acting on an object is proportional to its acceleration ($F = ma$) and equals the rate of change of linear momentum ($F = \frac{\Delta(mv)}{\Delta t}$).

Newton's Third Law of Motion

When an object exerts a force on a second body, the second body exerts an equal in magnitude and opposite in direction force on the first object.

Mass

A property of a physical body that represents a measure of its resistance to acceleration.

Linear Momentum

The product of an object's mass and its velocity ($\text{momentum} = mv$).

Terminal Velocity

The constant velocity reached by a falling object when the upward resistive drag force equals its downward weight, causing the resultant force to become zero.

Principle of Conservation of Momentum

The principle stating that total momentum is conserved in any interaction where no external resultant forces act.

Elastic Collision

A collision in which both total linear momentum and total kinetic energy are conserved, meaning relative speed of approach equals relative speed of separation.

Inelastic Collision

A collision where total momentum is conserved, but kinetic energy is not conserved, converting into other energy forms such as thermal or sound energy.

Centre of Gravity

The point at which the entire weight of an object can be considered to act.

Moment of a Force

The force multiplied by the perpendicular distance from the line of action of the force to the pivot point.

Couple

A pair of coplanar forces equal in magnitude but acting in opposite directions along different parallel lines of action, producing only rotation.

Torque of a Couple

The product of one of the forces in a couple and the perpendicular distance between the lines of action of the two forces.

Principle of Moments

For an object in rotational equilibrium, the sum of clockwise moments about a pivot must equal the sum of anticlockwise moments about that same pivot.

Density

The mass of a substance per unit volume ($\rho = \frac{m}{V}$), indicating how compact the material is.

Pressure

The force acting perpendicular to a surface per unit area ($p = \frac{F}{A}$).

Archimedes' Principle

The principle stating that the upthrust force exerted on a submerged body equals the weight of the fluid displaced by that body ($F = \rho g V$), arising from the hydrostatic pressure difference between the bottom and top surfaces.

Work Done

The product of the force causing a motion and the distance travelled in the direction of the force ($W = F s \cos(\theta)$), or the work done on a gas at constant pressure ($W = p\Delta V$).

Efficiency

The ratio of useful power output to total power input of a system, often expressed as a percentage: $\text{Efficiency} = \frac{\text{useful output power}}{\text{total input power}} \times 100\%$.

Principle of Conservation of Energy

Energy cannot be created or destroyed, only transferred from one form to another, meaning the total energy in a closed system remains constant.

Power

The rate at which energy is transferred or the rate of doing work ($P = \frac{\Delta W}{\Delta t} = Fv$).

Gravitational Potential Energy

The energy an object possesses due to its position in a gravitational field, calculated near Earth's surface as $\Delta E_p = mg\Delta h$.