3 ms·

You can't turn mass into force, especially not in space.

• brudgers 2y ago
  For the metrically challenged, pounds are a unit of force not mass.
  • littlestymaar 2y ago
    Wikipedia disagrees with you[1], and if pounds were a unit of weight that'd be very unpractical from a legal PoV to have things being labeled in pounds since the same object have a different weight in Puerto Rico (close to the Equator) and Fairbanks (close to the North Pole). [1]: https://en.wikipedia.org/wiki/Pound_(mass) https://en.wikipedia.org/wiki/Pound_(mass)
    • two_handfuls 2y ago
      I distinctly remember reading how I would weigh a different amount on the moon. This only makes sense if the pound is a unit of force.
      • stouset 2y ago
        You would weigh a different amount on the moon, but that is completely independent of how we label our units of measurement. The pound a unit of force. It is also a unit of mass. Both units share the same name.
        • two_handfuls 2y ago
          It's not independent because if I'm 80kg here, I'm still 80kg on the moon. Because gravity does not affect mass. If I weigh 160lb on earth I'm told that I would weigh 26lb on the moon. That makes sense if lb measures force because gravity affects force. In short, this commonly shared "fact" is consistent with pounds being a unit of force, not of mass. Or, I suppose, of lb at least sometimes being a unit of force.
          • stouset 2y ago
            If you weigh 160lb on the Earth, you also have 160lb of mass. You would weigh 26lb on the moon and still have 160lb of mass. I don’t know how to make the point any clearer that there are two units of measurement, both with the same name. https://en.m.wikipedia.org/wiki/Pound_(force) https://en.m.wikipedia.org/wiki/Pound_(force) https://en.m.wikipedia.org/wiki/Pound_(mass) https://en.m.wikipedia.org/wiki/Pound_(mass)
            • two_handfuls 2y ago
              So how do I know which is meant in a given sentence?
    • M3L0NM4N 2y ago
      I think it's used as both. Foot-pounds is used as a unit of work, so it's a force in that context.
    • delta_p_delta_x 2y ago
      To be very pedantic, the pound is a unit of both force and mass, and it's because the unit evolved before the Newtonian understanding of weight versus mass. That's why there exists the pound-mass, and the pound-force. Of course, in SI this is very straightforward: the unit of mass is the kilogram and the unit of force is the newton, which is the force acting on a mass of one kilogram experiencing an acceleration of one metre per second per second in an inertial frame of reference.
    • brudgers 2y ago
      Your comment is ambiguated. https://en.wikipedia.org/wiki/Pound https://en.wikipedia.org/wiki/Pound