Topic 1: key concepts

• What is the difference between mass and weight?

  Mass is a measure of the amount of matter in an object, while weight is the force exerted on an object due to gravity.
• what are the six main basic SI units?

  length = metre (m)

  mass = kilogram (kg)

  time = second (s)

  current = ampere or amp (A)

  temperature = kelvin (K)

  amount of a substance = mole (mol)
• what are the values of different multiples or prefixes?

  Metric prefixes: kilo (k), hecto (h), deca (da), deci (d), centi (c), milli (m) Binary prefixes: kilo (Ki), mega (Mi), giga (Gi), tera (Ti)