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Mass And Weight

Mass 

Mass is the amount of matter that makes up an object. It is measured in kilograms (kg). All masses have something called ‘intertia’ which is the tendency to continue moving if it is already in motion, or to stay still if already still. In other words, inertia is the resistance to change in motion. The larger the mass, the larger the intertia. 

Inertia is exactly why a large moving truck cannot stop as quickly as a smaller car can. Similarly, you can imagine the same truck will have more trouble speeding from a stationary position compared to a smaller vehicle which will accelerate faster. 

 

Weight

Whilst in every day life the term ‘weight’ is often used as another word for mass, in science this is not the case.

Weight is actually defined as the force on a mass due to the earth’s gravity and is measured in newtons (N). The formula for weight is as follows:

W = Weight (N), m = mass (Kg), g = gravitational strength (N/Kg)

On earth the gravitational strength is 9.81 N/Kg. For the sake of your course however, you can say that it is 10 N/Kg which is also known as the acceleration of free fall (10m/s/s). 

In other words, 10 N/Kg (gravitational strength) is exactly the same as 10 m/s/s (acceleration)