- #1
Sabra
- 2
- 0
Hello,
I am self-studying an introductory mechanics textbook and while I feel I understand the material there pretty well, I came across across an online definition of position which seems at odds with the explanations and definitions in my book.
The definition that confused me is:
""Position is scalar; it has neither magnitude nor direction.
EDIT: A position vector refers to a location relative to an arbitrary reference origin. This is not the same as position. Being arbitrary, the reference origin can be moved, without moving or changing the position (location) of the object, but this will change the position vector. Think of it this way: put an object on a glass table. Place a grid, with an arbitrary zero point under the table with the object centered on the zero point. The postion vector is zero relative to the origin on the grid. Now, move the grid such that the zero point is no longer under the object. The object's absolute position on the table is unchanged, but its vector relative to the grid is now different. ""
"Absolute position" seems to contradict the principle that no reference frame is inherently more correct than another. Also, if this "absolute position" is not defined relative to any reference point, how would you identify it?
I think this definition is wrong (and appropriately, position should be a vector quantity, not a scalar one). Am I right?
I'd very much appreciate it if someone could shed some light on this for me. Thanks!
I am self-studying an introductory mechanics textbook and while I feel I understand the material there pretty well, I came across across an online definition of position which seems at odds with the explanations and definitions in my book.
The definition that confused me is:
""Position is scalar; it has neither magnitude nor direction.
EDIT: A position vector refers to a location relative to an arbitrary reference origin. This is not the same as position. Being arbitrary, the reference origin can be moved, without moving or changing the position (location) of the object, but this will change the position vector. Think of it this way: put an object on a glass table. Place a grid, with an arbitrary zero point under the table with the object centered on the zero point. The postion vector is zero relative to the origin on the grid. Now, move the grid such that the zero point is no longer under the object. The object's absolute position on the table is unchanged, but its vector relative to the grid is now different. ""
"Absolute position" seems to contradict the principle that no reference frame is inherently more correct than another. Also, if this "absolute position" is not defined relative to any reference point, how would you identify it?
I think this definition is wrong (and appropriately, position should be a vector quantity, not a scalar one). Am I right?
I'd very much appreciate it if someone could shed some light on this for me. Thanks!