12.2 Definitions, Terminology, Units and Abbreviations

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

(a) distance;

• metre (m)

(b) time;

• second (s)

(c) velocity;

• metres/second (m/s)

(d) mass;

• kilogram (kg)

(e) volume;

• cubic metre (m³)

(f) temperature;

• kelvin (K)
  • when measured from absolute zero
   

• The degree Celsius (ºC)
  • when measured from the freezing point of water
   

(g) altitude.

• 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. 
• 1kg of mass on the earth is the same as 1kg of mass on the moon.

Weight (W)

• the force produced by gravitational attraction between masses.
• Weight = mass x gravity (W = mg)
• because the earth is larger than the moon, 1kg of mass is heavier on the earth than on the moon.

Gravitational Force (g)

• is the force of attraction between two objects due to their masses and the distance between them.
• the bigger the object, and the closer the distance, the bigger the force.
• Earth has a value of 9.81 m/s² at its surface.
• The Moon has a value of 1.62 m/s²

(b) inertia;

• A property of matter by which it continues in its existing state of rest or uniform motion in a straight line.
• More mass = more inertia.
• Newton's first law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force.