### Heisenberg Uncertainty-Which numbers to use? Sig Figs?

Posted:

**Sat Oct 08, 2016 5:04 pm**If a problem tells you (just making up an example) that something with the mass of 10 kg is going at the speed of 3.50 m/s plus or minus .4 m/s, which number would you use to solve the for the momentum? Would delta x be .4 + .4= .8 m/s? And if so, does that mean that in your answer you would only have one sig fig (or do the sig figs still correspond to the 3.50m/s, and in that case have 3)?

Thanks in advance!

Thanks in advance!