## Quiz 1 Fall 2015 #3 [ENDORSED]

$\Delta p \Delta x\geq \frac{h}{4\pi }$

Chin_Alyssa_3I
Posts: 34
Joined: Fri Jul 22, 2016 3:00 am

### Quiz 1 Fall 2015 #3

Find the uncertainty in the position of a marble of bass 1.5 g given that its speed is known to within plus or minus .55 m/s

My question is whether the uncertainty in velocity is .55 or is it the difference...(.55 - -.55 = 1.10)?

Katelyn Li 2J
Posts: 27
Joined: Wed Sep 21, 2016 3:00 pm

### Re: Quiz 1 Fall 2015 #3  [ENDORSED]

I think in this case it should be 1.10 because that's the whole range of the potential speed.

For example, some object with a speed of 9 m/s and an uncertainty of plus or minus 1 m/s means it could be 8 m/s or 10 m/s. Therefore, the uncertainty would be 2 m/s.

Minh_Le_3I
Posts: 10
Joined: Wed Sep 21, 2016 2:56 pm

### Re: Quiz 1 Fall 2015 #3

Are we suppose to double the speed if its +/- to cover the entire range in all Heisenberg uncertainty problems then?

Ara Yazaryan 1E
Posts: 44
Joined: Wed Sep 21, 2016 2:59 pm

### Re: Quiz 1 Fall 2015 #3

Minh_Le_3I wrote:Are we suppose to double the speed if its +/- to cover the entire range in all Heisenberg uncertainty problems then?

Correct me if I am wrong, but on the Heisenberg problem in the practice quiz we turn in we do not double it because we want the minimum error and adding that uncertainty would rather give the maximum error.

If someone can elaborate please do.