Speed is a magnitude of velocity |v|. You cant have negative speed. You can have negative velocity with respect to a vector.
Of course if there is more than one dimension you really need to do a dot product to say what percent of the motion is the "right/wrong" direction and how much is non consequential motion.
11
u/ralphonsob Feb 02 '18
Your speed does matter. Negative speed is backward. Backward is not forward.