Originally Posted by
Whiternoise
Take weight and mass for instance. Both are commonly interchanged in everyday language - and fair enough. Generally people don't need to know the difference and only need to know "oh it weighs 10kg" even though that's technically incorrect. However, as soon as you step into the realm of physics, it is grossly inaccurate to label weight and mass as the same thing. 10kg is a mass, 98N is the corresponding weight (in a grav. field of strength g). If you made this kind of gaffe in a physics paper it would cause uproar.