What makes a measurement meaningful?
What makes a measurement meaningful?
A physical quantity is something that can be measured and written as a number with a unit. Saying "length = 2.0" is incomplete, because 2.0 m2.0\text{ m}2.0 m, 2.0 cm2.0\text{ cm}2.0 cm and 2.0 km2.0\text{ km}2.0 km are all fundamentally different values.