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### Delta V value

Posted: **Tue Oct 27, 2020 4:41 pm**

by **Victoria Dao 3G**

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?

### Re: Delta V value

Posted: **Tue Oct 27, 2020 4:53 pm**

by **Selena Quispe 2I**

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!!

### Re: Delta V value

Posted: **Tue Oct 27, 2020 4:54 pm**

by **Kailani_Dial_2K**

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

### Re: Delta V value

Posted: **Tue Oct 27, 2020 4:58 pm**

by **Victoria Dao 3G**

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.

### Re: Delta V value

Posted: **Tue Oct 27, 2020 4:58 pm**

by **Victoria Dao 3G**

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!

### Re: Delta V value

Posted: **Tue Oct 27, 2020 8:19 pm**

by **Vanessa Perez**

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!