12.2 Definitions, Terminology, Units and Abbreviations

12.2.2 State the International System (SI) and ICAO units used to express:

(a) distance;

SI Unit: metre (m)

(b) time;

SI Unit: second (s)

(c) velocity;

SI Unit: metres per second (m/s)

ICAO Unit: knots (kt)

(d) mass;

SI Unit: kilogram (kg)

(e) volume;

SI Unit: cubic metre (m³)

(f) temperature;

SI Unit: kelvin (K)

ICAO Unit: degrees Celsius (°C)

(g) altitude.

ICAO Unit: feet (ft)

12.2.4  Define and where appropriate show the relevant relationships between:

(a) mass, weight and gravitational force (g);

Mass (m):

• The amount of matter in an object
• Constant, does not change with location
• Unit: kilogram (kg)

Weight (W):

• The force due to gravity acting on a mass
• Varies with the strength of the gravitational field
• Unit: Newtons (N)

Gravitational Force (g):

• The acceleration due to gravity acting toward the centre of a body
• On Earth: approximately 9.81 m/s²

Relationship:

• Weight = Mass × Gravity
• W = m × g

Key Point:

• Mass remains constant
• Weight changes depending on gravitational force (g)

Summary:
Mass is the quantity of matter, weight is the force due to gravity, and they are related by W = m × g.

(b) inertia;

• The property of matter that resists any change in its state of rest or uniform motion in a straight line