Question

10. How would you determine the mass of an object on the space station in space?

Answer 1

Well, in Newtonian mechanics, mass is the ratio of momentum to velocity or force to acceleration, so you need to put a calibrated net force on it and measure the acceleration (or vice versa). That's conceptually simple but probably very tricky to do with any accuracy because (i) objects aren't perfectly rigid, so you need to accelerate them slowly and/or give them plenty of time to settle down to be sure that all the parts are accelerating at the same rate, which means your weighing contraption will be very large, (ii) in particular, the most convenient way to apply a constant acceleration in a compact device is normally to use a centrifuge, but the acceleration depends on the radius, so if you have a tall object, the top parts of it will count for less, and (iii) unless you're weighing very small things, you don't have an approximately infinite mass to apply forces from, so you'll have to measure the acceleration of your contraption and subtract that off.