Mass and weight
Mass
The amount of matter an object contains. Mass is measured in kilograms (kg) or grams (g). is the amount of matter in an object. Mass is measured in A kilogram is a unit of mass. (kg).
Weight is the force of gravity on your mass.
The force of attraction between all objects. The more mass an object has, the larger the force of gravity it exerts. is a force that attracts mass together.
Weight is the name given to the force caused by the Earth’s mass attracting an object’s mass. Weight is measured in Unit of force named after British scientist Isaac Newton (1642-1727), eg the frictional force on the boat is 20,000 N. (N).
The relationship between the weight of an object, its mass and the gravitational field strength is shown in the following formula,
\(\text{weight (N)}=\text{mass (kg)}\times\text{gravitational field strength (N/kg)}\)
\(\text{W}=\text{m}\times\text{g}\)
Gravitational field strength is given the letter g. In this context, this g does not represent the mass measurement grams.
The Wmg triangle can be used to find weight (W), or mass (m) or gravitational field strength (g).
Question
Find the weight of a person on Earth if they have a mass of 65 kg (g = 10 N/kg)
W = m × g
= 65 kg × 10 N/kg
= 650 N
Question
When do you become weightless?
If you travel away from Earth, gravitational field strength reduces. When g becomes 0 N/kg, you are weightless.