Newton's Third Law
Forces and Motion

All kinds of arrows

Teaching Guidance for 14-16 Supporting Physics Teaching

Consistent representations support understanding

We've emphasised using arrows for representing physical quantities that are vectors, as a supplement to verbal and algebraic representations. The main reason for this is to emphasise the vector nature of the quantities – something that can all too quickly get lost if you focus on processes that can be described in one dimension.

It's important to be able to differentiate between the arrows, so be consistent. Either develop your own conventions for different quantities (different styles of arrowhead, maybe – but we'd suggest not different thicknesses as the primary differentiator), or use the SPT arrows developed here. In either case, be clear and consistent.

Newton's Third Law
is used in analyses relating to Collisions
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