Some people get confused between mass and weight.

The mass of an object always stays the same, so if a person has a mass of 50kg, this will be her mass on Earth, on the moon, and anywhere else. The weight however depends on their environment, so although they may weight 500 Newtons on earth, their weight on the moon could be 80 Newtons. In normal speech, people often get the two mixed up, which is kind of ok, but in mathematics it’s not ok!

Kilogram

The kilogram is the SI unit of measure. It is about the mass of single bag of sugar. Related to the kilogram is the gram and the tonne. A kilogram is a thousand grams and a tonne is a thousand kilograms. What would you need to do to convert between these measures? Let’s try a few.

Exercise

Answers