Physics Paper 1 Key Knowledge

Flashcards covering key knowledge for Physics Paper 1 including Motion, Forces, Energy, Waves, the EM Spectrum, and Atoms and Radiation.

Scalar quantity

A quantity that has magnitude (size) but no direction.

Vector quantity

A quantity that has both magnitude and a specific direction.

Displacement

A vector quantity representing distance in a certain direction.

Examples of vector quantities

Displacement, velocity, acceleration, force, weight, and momentum.

Examples of scalar quantities

Distance, speed, mass, energy, and temperature.

Velocity

Speed in a specific direction.

Average speed equation

$$\text{Average speed (m/s)} = \text{distance (m)} \div \text{time (s)}$$

Distance travelled equation

$$\text{Distance travelled (m)} = \text{average speed (m/s)} \times \text{time (s)}$$

Gradient of a distance/time graph

Represents the speed of an object.

Acceleration equation

$\text{Acceleration (m/s}^2) = \text{change in velocity (m/s)} \div \text{time taken (s)}$ or $a = \frac{v}{t}$

Final velocity squared equation

$v^2 - u^2 = 2ax$ where $v$ is final velocity, $u$ is initial velocity, $a$ is acceleration, and $x$ is distance.

Gradient of a velocity/time graph

Represents the acceleration of an object.

Area under a velocity/time graph

Represents the distance travelled.

Typical walking speed

$$1.5\,m/s$$

Typical running speed

$$3\,m/s$$

Typical cycling speed

$$6\,m/s$$

Speed of sound

$$330\,m/s$$

Acceleration due to free fall

Approximately $10\,m/s^2$

Newton's First Law

An object at rest will remain at rest and an object in motion will continue moving at a constant velocity, unless acted upon by an external force.

Newton's Second Law equation

$\text{Force (N)} = \text{mass (kg)} \times \text{acceleration (m/s}^2)$ or $F = ma$

Weight

The force exerted by gravity on an object.

Weight equation

$$\text{Weight (N)} = \text{mass (kg)} \times \text{gravitational field strength (N/kg)}$$

Centripetal force

The resultant force that acts towards the centre of a circle, keeping an object in circular motion.

Newton's Third Law

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

Momentum equation

$$\text{Momentum (kg m/s)} = \text{mass (kg)} \times \text{velocity (m/s)}$$

Conservation of momentum

The momentum before a collision is equal to the momentum after a collision.

Stopping distance

$$\text{Thinking distance} + \text{braking distance}$$

Efficiency equation

$$\text{Efficiency} = \frac{\text{useful energy transferred by the device}}{\text{total energy supplied to the device}}$$

Gravitational potential energy (GPE) equation

$GPE = \text{mass} \times \text{height} \times g$ where $g = 10\,N/kg$ on Earth.

Kinetic energy equation

$$\text{Kinetic energy} = \frac{1}{2} \times \text{mass} \times (\text{speed})^2$$

Principle of conservation of energy

Energy cannot be created or destroyed; it can only be transferred from one form to another.

Frequency

The number of complete oscillations or cycles of a wave that occur in one second ($hertz, Hz$).

Amplitude

The maximum displacement of particles in a wave from their equilibrium position.

Period

The time taken for one complete oscillation or cycle of a wave: $\text{Period} = \frac{1}{\text{frequency}}$

Longitudinal wave

A wave where particles of the medium oscillate parallel to the direction of wave propagation (e.g., sound waves).

Transverse wave

A wave where particles of the medium oscillate perpendicular to the direction of wave propagation (e.g., electromagnetic waves).

Wave speed equations

$\text{Wave speed (m/s)} = \text{frequency (Hz)} \times \text{wavelength (m)}$ or $\text{Wave speed (m/s)} = \text{distance (m)} \div \text{time (s)}$

Wavelength

The distance between two corresponding points on a wave, such as two crests or two troughs (measured in metres, $m$).

Speed of electromagnetic waves

$3 \times 10^8\,m/s$ in a vacuum.

The EM Spectrum order

Radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma rays.

Isotope

An atom that has the same number of protons, but a different number of neutrons.

Ion formation

An atom will become a positive ion if it loses an electron.

Becquerel (Bq)

The unit of activity for a radioactive isotope, representing the number of decays per second.

Half-life

The time taken for half of the undecayed nuclei in a radioactive sample to decay.

Contamination

The presence of radioactive substances on or in objects.

Irradiation

Being exposed to ionising radiation.