Relativity?

what does that mean "a body moves relative to air"?





n do we use this term "relative" only for objects in same reference frame?|||It's all to do with inertial frames of reference. E.g. If you were in a car and travelling at 60km/h and somebody fired a gun of which the bullet was travelling at 60km/h also, to YOU (traveling in the same F.o.R) its relative speed would be 0km/h because for you it would seem to be standing still. The term relative IS used when talking about frames of reference and it is used, usually to describe something being compared to another, i.e the bullet's speed relative to the car(you)|||To simply give the object's velocity is meaningless without referring to a reference frame. "Relative to the air" means in the frame in which the air is motionless.