Physics: Chapter 4 - Mass, Weight and Density

4.1 Mass and Weight
Mass is a measure of the amount of matter or substance in a body.
SI Unit: kilogram (kg)

Weight is a force and has direction.
SI Unit: newton (N)
Also know as gravity.

W = mg
Weight = mass(gravitational field strength)
Earth = 10kg^-1

4.2 Inertia
Inertia of an object refers to the reluctance of the object to change its state of rest or motion.

4.3 Density
The density of a substance is defined as its mass per unit volume.
p = m/v
Density = mass/ volume
SI Unit: kilogram per cubic metre (kg m^-3)