Is the textbook wrong or am I?

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In summary, the conversation is about a vertical spring with a spring constant of 875 N/m that is compressed by 0.160 m and attached to a table. The question is asking for the upward speed that the spring can give to a 0.380 kg ball when released. The solution involves using conservation of energy and taking into account the displacement and gravity. The book's answer is 7.47 m/s, while the person in the conversation got 7.68 m/s, but after further discussion it was determined that the book's answer was correct.
  • #1
drewdiddy
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Homework Statement



A vertical spring (ignore its mass), whose spring constant is 875 N/m is attached to a table and is compressed down by .160 m. (a) What upward speed can it give to a .380 kg ball when released?


Homework Equations



Conservation of Energy using 1/2 k x^2 for Uspring.

The Attempt at a Solution



I get 7.68 m/s for the velocity and the book gets 7.47 m/s. Wanted to see who was right and if I'm doing something wrong.
 
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  • #2
drewdiddy said:

Homework Statement



A vertical spring (ignore its mass), whose spring constant is 875 N/m is attached to a table and is compressed down by .160 m. (a) What upward speed can it give to a .380 kg ball when released?


Homework Equations



Conservation of Energy using 1/2 k x^2 for Uspring.

The Attempt at a Solution



I get 7.68 m/s for the velocity and the book gets 7.47 m/s. Wanted to see who was right and if I'm doing something wrong.

"Upward" also means against gravity. You should also figure as an adjustment the m*g*h over the displacement of the acceleration.
 
  • #3
So you're saying you got the book's answer?

I used the conservation of energy subbing values for spring and taking into account y=0 when crossing the original spring length. I'm quite sure I have the right answer and the book's is wrong but I just want to verify.
 
  • #4
drewdiddy said:
So you're saying you got the book's answer?

I used the conservation of energy subbing values for spring and taking into account y=0 when crossing the original spring length. I'm quite sure I have the right answer and the book's is wrong but I just want to verify.

I'm just saying that

mv2/2 = kx2/2 - m*g*x
 
Last edited:
  • #5
You are wrong, your book is right, Pion is right: (except I would not use both "h" and "x", there is only one vertical distance in the problem)
 
  • #6
borgwal said:
You are wrong, your book is right, Pion is right: (except I would not use both "h" and "x", there is only one vertical distance in the problem)

Thanks for the catch. Of course h and x are the same.

I edited the previous post to be correct now.
 

1. Is it common for textbooks to contain mistakes?

Yes, it is not uncommon for textbooks to contain mistakes. Textbooks are often written by a team of authors and go through multiple rounds of editing and revisions, but errors can still slip through. Additionally, new research and discoveries may contradict information in textbooks that were published years ago.

2. How can I determine if the textbook is wrong?

The first step is to carefully read and understand the information presented in the textbook. Then, you can cross-reference the information with other reliable sources, such as academic journals or reputable websites. If you find conflicting information, it is important to critically evaluate the sources and evidence before concluding that the textbook is wrong.

3. What should I do if I find a mistake in my textbook?

If you believe you have found a mistake in your textbook, you can bring it to the attention of your teacher or professor. They may be able to provide clarification or further explanation on the topic. You can also contact the publisher of the textbook to report the error. Many publishers have processes in place for correcting mistakes in future editions.

4. Can I trust the information in my textbook?

While textbooks are generally considered reliable sources of information, it is important to remember that they are not infallible. It is always a good idea to critically evaluate and fact-check the information presented in any source, including textbooks. Consulting multiple sources can help ensure the accuracy of the information.

5. What if I still have doubts about the information in my textbook?

If you are still unsure about the information presented in your textbook, you can consult with your teacher, professor, or a subject matter expert. They may be able to provide additional resources or explanations to help clarify any confusion. It is also important to continue researching and learning about the topic from a variety of sources to develop a well-rounded understanding.

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