The weightThe force acting on an object due to the pull of gravity from a massive object like a planet. The force acts towards the centre of the planet and is measured in newtons (N). of an object is defined as the force of gravity acting on the object. It may be thought of as acting at a single point called its centre of massThe amount of matter an object contains. Mass is measured in kilograms (kg) or grams (g).. Depending on the object's shape, its centre of mass can be inside or outside it.
The weight of an object and its mass are directly proportional. For a given gravitational field strength, the greater the mass of the object, the greater its weight.
This is when:
weight (W) is measured in newtons (N)
mass (m) is measured in kilograms (kg)
gravitational field strength (g) is measured in newtons per kilogram (N/kg) On Earth, g = 10 N/kg (approximately)
Weight can be measured using a spring-balance (newtonmeter) or a top-pan balance.
Example
An apple has a mass of 100 g. Calculate its weight on Earth.
