7th Edition, 1B.27


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Dimitri Speron 1C
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7th Edition, 1B.27

Postby Dimitri Speron 1C » Mon Oct 15, 2018 4:12 pm

The question asks us to find the minimum uncertainty in a bowling ball. In lecture Dr. Lavelle said when you are given a velocity + or - a certain value you use the entire range of values as your uncertainty. (i.e. the velocity is 1 m/s +/- 3 m/s, therefore your uncertainty is 6 m/s) The solution manual however just uses what I thought was 1/2 of the value of the uncertainty. It says that the ball's uncertainty is = 5m/s rather than 10, when the question thats that it is +/- 5 m/s, Which is the proper way to do it? Is the solution manual incorrect?

Adrian C 1D
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Re: 7th Edition, 1B.27

Postby Adrian C 1D » Mon Oct 15, 2018 5:43 pm

The solution manual is incorrect and the error is posted on the class website under "Solution Manual Errors".
You were correct to use 10 m/s for delta v and the correct answer is 6.7*10-37 m.

Lorena Zhang 4E
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Re: 7th Edition, 1B.27

Postby Lorena Zhang 4E » Wed Oct 17, 2018 11:15 pm

Does this rule also apply to the uncertainty in position? For example, when it's +-5m, is it that we should use 10m in the equation for uncertainty in position?

Chloe Qiao 4C
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Re: 7th Edition, 1B.27

Postby Chloe Qiao 4C » Fri Oct 19, 2018 10:02 am

I believe it applies to the uncertainty in position. My TA said if we are given a question about an atom or a sphere, we need to pay attention to whether the given value is radius or diameter, and we need to use the diameter value for delta X.


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