How to use a spring balance in space?

[reganw]

A spring balance cannot be used to measure the weight of anything under the conditions of a space shuttle. Is there any way you might use a spring balance to compare the 'heaviness' of twin babies born on the shuttle? Discuss.


I don't know how you'd use a spring balance in the shuttle.. Any suggestions?

 

[Integral]

Sure.

Just use the scale, maintained at a constant force, to accelerate the babies across the room.

Measure average velocity, compute acceleration. Force and acceleration give you mass.

It may take a bit of practice to be able to hold a constant force on the scale but it can be done.

 

[reganw]

Sure.

Just use the scale, maintained at a constant force, to accelerate the babies across the room.

Measure average velocity, compute acceleration. Force and acceleration give you mass.

It may take a bit of practice to be able to hold a constant force on the scale but it can be done.

So to maintain the scale at a constant force, you mean apply pressure to the scale myself, sit the baby on it and let go so that the baby would accelerate?

 

[BenR-999]

perhaps a less harmful way would be to accelerate the spaceship at a constant acceleration. (for convenience let's accelerate the spaceship at 9.8ms^-2)
This acceleration would mean the conditions in the spaceship are identical to those in a gravitational field, the the spring balance would work fine.

 

[reganw]

Oh okay, thank you to the both of you, you've been very helpful :)

 

[gneill]

Instead of flinging babies around the cabin at the end of a spring, consider that springs with a mass load also oscillate about an equilibrium point given a little nudge.

 

[BenR-999]

question kind of resembles the famous 'barometer' question dismissed by Bohr in his school examination...
why don't we go to the pilot of the space centre and say "I'll give you this nice spring balance if you tell me how heavy this baby is"

..by the way, i think gneill's solution is the best - by far the easiest to actually achive...although you physically can't get away from the fact that the baby's mass will be measured in terms of 'k' the spring constant..but that's ok