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Uncertainty Principle

Posted: Thu Nov 02, 2017 10:12 pm
Hi!!

I have a question regarding the Uncertainty principle. If given a problem where the momentum uncertainty, for example, is + or - 2, does that mean the uncertainty amount is 4? Or do you have to take into account the value of the momentum?

Thanks!

Re: Uncertainty Principle

Posted: Thu Nov 02, 2017 10:18 pm
The uncertainty amount is 4. You don't need to take into account the actual momentum value.

Re: Uncertainty Principle

Posted: Thu Nov 02, 2017 10:38 pm
Also if you use number 1.45 as a practice problem, the solutions manual is incorrect. The actual velocity given is 5.00 $\pm$ 5.0m/s
Thus, $\Delta v$=10.0m/s NOT 5.0m/s as the solution manual incorrectly states. Therefore, your answer is $\Delta x$=6.7x10-37m

Re: Uncertainty Principle  [ENDORSED]

Posted: Sat Nov 11, 2017 9:29 am
An easy way to remember this is to think of delta v as the change in v like in math. So, we arent concerned with the value of v, but rather the difference between the two limits to its domain.

Re: Uncertainty Principle

Posted: Sat Nov 11, 2017 5:23 pm
If it's +/- 4. its easier to write it out like this

(4+4)-(4-4)

Re: Uncertainty Principle

Posted: Sat Nov 11, 2017 7:57 pm
The uncertainty is 4. If the problem states +/- 2, that means 2 from 0 both ways, added together, gives you four.