Physics P2 not complete

force

A push or pull on an object that can change its motion or shape

resultant force

The single force that represents the combined effect of all forces acting on an object

scalar

Quantity with magnitude only

vector

Quantity with magnitude and direction

mass

The amount of matter in an object (kg)

weight

Force due to gravity on an object’s mass

normal contact force

Support force from a surface acting perpendicular to it

friction

Force opposing motion between surfaces

air resistance

Force opposing motion through air

balanced forces

Forces equal in size and opposite in direction with no change in motion

unbalanced forces

Forces that cause a change in motion because resultant ≠ 0

acceleration

Rate of change of velocity (m/s²)

velocity

Speed in a given direction

distance

How far an object moves

displacement

Distance in a specific direction

F = m × a

Force (N) = mass (kg) × acceleration (m/s²)

a = (v − u) / t

Acceleration = change in velocity ÷ time

v = s / t

Speed = distance ÷ time

W = F × s

Work done (J) = force × distance (m)

pressure = force / area

Pressure in fluid (Pa = N/m²)

F = k × e

Force on a spring = spring constant × extension

E (spring) = ½ × k × e²

Elastic potential energy stored in a spring

v = f × λ

Wave speed = frequency × wavelength

wavelength

Distance between two adjacent identical points on a wave

frequency

Number of waves passing a point per second (Hz)

amplitude

Maximum displacement from rest position

transverse wave

Oscillations perpendicular to direction of energy transfer

longitudinal wave

Oscillations parallel to direction of energy transfer

compression

Region of high pressure in a longitudinal wave

rarefaction

Region of low pressure in a longitudinal wave

sound wave

Longitudinal mechanical wave

EM wave

Transverse wave that can travel through a vacuum

human hearing range

Approximately 20 Hz to 20 kHz

spring extension

Increase in length when a force is applied

limit of proportionality

Point where Hooke’s law no longer applies

elastic deformation

Returns to original shape after force removed

inelastic deformation

Does not return to original shape after force removed

terminal velocity

When drag force equals weight so resultant force = 0 and speed is constant

Newton’s First Law

An object continues in uniform motion or rest unless a resultant force acts

Newton’s Second Law

Acceleration ∝ resultant force and inversely ∝ mass (F = m × a)

Newton’s Third Law

For every action there is an equal and opposite reaction

method ripple tank

Measure wavelength using ruler; measure time for N waves; calculate v = f × λ

method sound speed in air

Measure distance between source and detector; time taken; use v = d/t

effect of medium on wave

Frequency stays same; speed and wavelength change

refraction

Change in speed causes change in direction at boundary; frequency constant

X-ray usefulness

High penetration useful for imaging

X-ray hazard

Ionising energy can damage cells and DNA

label wave diagram

Show crest, trough, wavelength, amplitude

calculate acceleration from F and m

Use a = F/m; substitute values; include units

calculate work done

Use W = F × s; substitute values; include units

calculate spring constant

k = F/e

calculate elastic potential energy

E = ½ × k × e²

formula to find unknown force, mass, or acceleration

use F = m × a

interpret distance-time graph

Gradient = speed; flat = stationary

interpret velocity-time graph

Gradient = acceleration; area under graph = distance

effect of increasing frequency

More waves per second; shorter wavelength if speed constant

why sound can’t travel in vacuum

No particles to transmit longitudinal wave energy