# Homework Help: Minimum uncertainty in position

1. Jun 17, 2007

### [webmaster]

1. The problem statement, all variables and given/known data
Determine the minimum uncertainty in position for an electron moving with velocity 4 km/s, if the relative uncertainty in its momentum is 0,004.

2. Relevant equations

3. The attempt at a solution

2. Jun 17, 2007

### malawi_glenn

You will never get any help here if you dont write down your work so far, thoughts, equations and so far..

3. Jun 17, 2007

### [webmaster]

sorry, i didn't know this is the procedure.

i tried to solve the problem by myself, but i'm missing something...

do i need to use the plack's constant in this problem?

and also, which equation should I use

deltaX*deltaP=h/2 or a different one.

Could you give me a hint where to statr from

4. Jun 17, 2007

### Moridin

5. Jun 17, 2007

### [webmaster]

6. Jun 17, 2007

### malawi_glenn

yes, how is momentum related to momentum?

7. Jun 17, 2007

### [webmaster]

it looks like you gouys are enjoying yourselves...

it's obvious that i'm not good at physics, you don't need to laugh at me

8. Jun 17, 2007

### malawi_glenn

What? We are trying to make you think for yourself, that is how one gets better at something. And i Spelled wrong, I was talking in the phone meanwhile I wrote "yes, how is momentum related to momentum?", and i am a boy, can not do two things at the same time.

How is momentum related to velocity?

And when you have found ot the momentum of the electron, you use the data given, that a certain amount of the momentum is considered as "uncertanty". For example: if the momentum is 500 and the relative uncertainty is 0.01, the uncertainty in momentum is 0.01 * 500 = 50.

These forums have helped a lot of people, no one is making fun of each others. We have all made VERY bad mistakes here :)

9. May 15, 2008

### Ana.B

If we are considering the heisenberg uncertainty principal and we have a position of an electron which is determined to within 0.1nm. and I have to find the minimum uncertainty in position...

momentum p = h/L where L is the wavelength.....and then from here what do i do>>>>>

thanks:)

10. Jan 4, 2011

### slavi_w

Need help with the same problem .

Thank you !!!