AQA GCSE Physics Paper 2: Forces, Waves, and Electromagnetism

These flashcards cover key definitions, formulas, and laws from AQA Combined Higher Physics Paper 2 (Forces, Waves, EM Spectrum, and Magnetism), designed for Grade 8-9 revision.

Scalar

A quantity that has magnitude only, such as distance, speed, time, energy, and work done.

Vector

A quantity that has both magnitude and direction, such as velocity, acceleration, force, displacement, and momentum.

Speed

A measure of how quickly an object travels, calculated using the equation $v = \frac{d}{t}$, where $v$ is speed in $\text{m/s}$, $d$ is distance in $\text{m}$, and $t$ is time in $\text{s}$.

Velocity

The speed of an object in a given direction; changing direction results in a change in velocity even if speed remains constant.

Distance-Time Graph Gradient

The gradient of this graph represents the speed of the object; a steeper line indicates a greater speed.

Acceleration

The rate of change of velocity, calculated as $a = \frac{v - u}{t}$, where $a$ is acceleration, $v$ is final velocity, $u$ is initial velocity, and $t$ is time.

Velocity-Time Graph Gradient

The gradient of this graph represents the acceleration of the object.

Area Under Velocity-Time Graph

The total area under the line on this graph represents the distance travelled.

Newton's First Law

The law stating that an object will stay at rest or continue at a constant velocity unless acted upon by a resultant force.

Inertia

The tendency of an object to stay at rest or continue at a constant velocity.

Newton's Second Law

The law stating that resultant force causes acceleration, governed by the equation $F = ma$, where force is proportional to acceleration and inversely proportional to mass.

Newton's Third Law

Whenever two objects interact, they exert equal and opposite forces on each other.

Stopping Distance

The sum of the Thinking Distance and the Braking Distance.

Thinking Distance

The distance travelled before the driver applies brakes, affected by tiredness, alcohol, drugs, and distractions.

Braking Distance

The distance travelled after the brakes are applied, affected by speed, vehicle mass, road conditions, and brake or tyre condition.

Braking Distance Square Law

Braking distance increases roughly with the square of speed; for example, doubling the speed quadruples the braking distance.

Terminal Velocity

The constant speed reached when weight equals air resistance, resulting in a resultant force and acceleration of $0$.

Hooke's Law

The extension of a spring is directly proportional to the force applied ($F = ke$), provided the limit of proportionality is not exceeded.

Elastic Potential Energy

The energy stored when a spring is stretched, calculated as $E_e = \frac{1}{2}ke^2$.

Momentum

A measure of motion calculated by the equation $p = mv$, where $p$ is momentum in $\text{kg\,m/s}$, $m$ is mass, and $v$ is velocity.

Conservation of Momentum

The principle that total momentum before a collision equals the total momentum after a collision, provided no external forces act.

Wave

A transfer of energy without the transfer of matter.

Transverse Waves

Waves where oscillations are perpendicular to the direction of energy transfer, such as light, radio waves, or water waves.

Longitudinal Waves

Waves where oscillations are parallel to the direction of energy transfer, containing compressions and rarefactions, such as sound waves.

Wavelength ($\lambda$)

The distance between identical points on consecutive waves, such as crest to crest or compression to compression.

Frequency ($f$)

The number of complete waves passing a point each second, measured in Hertz ($\text{Hz}$).

Wave Equation

The fundamental relationship for waves: $v = f\lambda$, where $v$ is wave speed, $f$ is frequency, and $\lambda$ is wavelength.

Refraction

The process where a wave changes direction because its speed changes when entering a different medium.

Diffraction

The spreading out of waves after passing through a gap, which is most noticeable when the gap size equals the wavelength.

Electromagnetic (EM) Spectrum

A group of transverse waves that all travel at the speed of light ($3 \times 10^8\,\text{m/s}$) in a vacuum, ordered: Radio, Microwave, Infrared, Visible Light, Ultraviolet, X-rays, Gamma Rays.

Microwaves

EM waves used for mobile phones, satellite communication, and cooking because they can pass through the atmosphere.

Ionising Radiation Dangers

X-rays and Gamma rays can damage DNA because they are highly ionising.

Induced Magnets

Temporary magnets that become magnetic only when placed in an existing magnetic field.

Electromagnets

Magnets produced by current in a coil whose strength can be increased by increasing current, increasing the number of turns, or adding a soft iron core.

Right-hand grip rule

A rule used to find the magnetic field direction around a wire: the thumb points with the current and fingers curl in the field direction.

Motor Effect

The force experienced by a current-carrying conductor when placed in a magnetic field, used in motors and loudspeakers.