Paul, while your plane is on the runway, with its wheels stationary, climb on to the top of the plane, stick the end of a length of string to the top - use your chewing gum if you like - now come down and stick the other end to the ground, vertically below the chewing gum. If the top of the plane is moving relative to the ground your string will not remain vertical for long, and the plane will distort. Ergo, the top of the plane is stationary relative to the ground.
if the plane is sitting on the ground , it is moving.
and it is moving faster than the ground.
the top of the plane is 50 ft higher than the ground.
it is moving faster than the ground.
you even agree in the below.
Similarly, in the case of the record; of course the outer edge is moving faster than the inner, relative to the surroundings, which for the sake of illustration, can be taken to be stationary; but any point on the outside of the record never changes its position relative to any other part of the record. That in my understanding is what constitutes being stationary relative to something.
and the top of the plane is like the outer edge.
