- #1

etotheipi

A video on the MIT open courseware site, https://ocw.mit.edu/courses/physics/8-01sc-classical-mechanics-fall-2016/week-2-Newtons-laws/7.1-pushing-pulling-and-tension/, defines tension as the magnitude of the force between any two adjacent segments (A and B) of string - that is, ##T = |\vec{F_{AB}}| = |\vec{F_{BA}}|##. For simplicity, I'll just try to understand a massless string/spring first where tension is uniform! This seems consistent with ##T = k|\Delta x|##. My previous understanding is that the tension was just the magnitude of the force exerted on any object in contact with any segment of the string, most commonly (but not necessarily) the ends, the direction of which can be worked out by a little common sense and a FBD (i.e. extension or compression...).

However I've also seen it referred to as a rank-1 tensor - I haven't really covered tensors so this might be a little out of my depth - though I understand this to be sort of like a vector. But if my string is curved around a pulley somewhere, I could separate it into lots of little slices and the tension forces would all point in slightly different directions, so one vector for "tension" doesn't seem good enough!

I wonder whether someone could shed some light on this? Thanks!

However I've also seen it referred to as a rank-1 tensor - I haven't really covered tensors so this might be a little out of my depth - though I understand this to be sort of like a vector. But if my string is curved around a pulley somewhere, I could separate it into lots of little slices and the tension forces would all point in slightly different directions, so one vector for "tension" doesn't seem good enough!

I wonder whether someone could shed some light on this? Thanks!

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