I had an interesting debate with a friend of mine recently. They claim that a stationary object (we are JUST talking about our reference frame here) observed by us has a constant velocity, even if it is 0.
However, I claim that since velocity is a vector quantity, which requires both magnitude and direction, we cannot attribute any velocity to a stationary object since it's direction is undefined. We can only state that its SPEED is zero (and also constant) as speed, being a scalar, is simply a numerical value which in this case does not change. I concede that one COULD argue that we simply take an XYZ graph (if working in 3D, for example), and simply state that each velocity component is zero (and constant). However, I claim that this is not a solution to the above argument but a crude workaround.
A quick googling has unfortunately not revealed the answer, as I mainly get results from pages such as GCSE bitesize and the likes. :uhh:
However, I claim that since velocity is a vector quantity, which requires both magnitude and direction, we cannot attribute any velocity to a stationary object since it's direction is undefined. We can only state that its SPEED is zero (and also constant) as speed, being a scalar, is simply a numerical value which in this case does not change. I concede that one COULD argue that we simply take an XYZ graph (if working in 3D, for example), and simply state that each velocity component is zero (and constant). However, I claim that this is not a solution to the above argument but a crude workaround.
A quick googling has unfortunately not revealed the answer, as I mainly get results from pages such as GCSE bitesize and the likes. :uhh: