Delta V value

$H_{\psi }=E_{\psi }$

1-D: $E_{TOTAL}\psi (x)=E_{k}\psi (x)+V(x)\psi(x)=-\frac{h^{2}}{8\pi ^{2}m}\frac{d^{2}\psi(x)}{dx^{2}}+V(x)\psi(x)$

Victoria Dao 3G
Posts: 65
Joined: Wed Sep 30, 2020 9:50 pm

Delta V value

Hi! I'm still a bit confused as to when we should be doubling and when we are not supposed to double the delta v value. For example, for question 27 from 1B in the textbook (A bowling ball of mass 8.00 kg is rolled down a bowling alley lane at 5.00 ± 5.0 m⋅s-1. What is the minimum uncertainty in its position?), the answer involves NOT doubling the 5ms-1, but why would we not double the delta v value if the value is given as ± 5.0 m⋅s-1?

Selena Quispe 2I
Posts: 91
Joined: Wed Sep 30, 2020 10:01 pm
Been upvoted: 3 times

Re: Delta V value

Hi! So the textbook answer is wrong and Lavelle clarifies this through his Solution Manual Sheet on his website! You were supposed to double in this problem! I hope this helps!!

Kailani_Dial_2K
Posts: 114
Joined: Wed Sep 30, 2020 9:44 pm
Been upvoted: 4 times

Re: Delta V value

Hello, did you check to see if this was one of the questions in the textbook with an incorrect solution? The correct way to approach this problem would be to double the 5 to get a change in velocity of 10. You would not double the velocity if it said something like the change in velocity is equal to 1% of the speed of light. Because you would just take the 1% of the speed of light and that would be your delta v. I hope this helps

Victoria Dao 3G
Posts: 65
Joined: Wed Sep 30, 2020 9:50 pm

Re: Delta V value

Selena Quispe 2G wrote:Hi! So the textbook answer is wrong and Lavelle clarifies this through his Solution Manual Sheet on his website! You were supposed to double in this problem! I hope this helps!!

Ah thank you so much! I was so confused haha.

Victoria Dao 3G
Posts: 65
Joined: Wed Sep 30, 2020 9:50 pm

Re: Delta V value

Kailani_Dial_3G wrote:Hello, did you check to see if this was one of the questions in the textbook with an incorrect solution? The correct way to approach this problem would be to double the 5 to get a change in velocity of 10. You would not double the velocity if it said something like the change in velocity is equal to 1% of the speed of light. Because you would just take the 1% of the speed of light and that would be your delta v. I hope this helps

Thank you, that makes a lot of sense!

Vanessa Perez
Posts: 76
Joined: Wed Sep 30, 2020 9:56 pm

Re: Delta V value

wow haha I was literally stuck on this problem for a while, it did not cross my mind that it was a mistake. Thank you all!