Originally Posted by
Jet_Fan
NASA are very clear in their example 'the wind speed is -20 mph' in reference to the plane. A high enough positive sign wind can produce a negative sign GS in reference to a plane. There is no absolute value rule in the calculation for GS.
I understand they used the term "speed", but they did so referencing a direction- that makes it a velocity.
Please answer my question regarding traveling at what you call a negative speed for a period of time- the displacement you have from your origin is a magnitude without sign or direction- that is what speed measures.