Problem with choosing which axis should be positive or negat

  • Thread starter Thread starter Frankenstein19
  • Start date Start date
  • Tags Tags
    Axis Positive
Click For Summary

Homework Help Overview

The discussion revolves around a physics problem involving a 14.0 kg bucket being lowered by a rope with a tension of 163 N. The focus is on understanding the implications of choosing positive and negative directions in the context of the problem.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the significance of sign conventions in physics problems, particularly regarding the choice of positive and negative directions. Questions arise about consistency in sign usage and the correctness of answers based on different sign choices.

Discussion Status

Participants are engaging in a productive dialogue about the flexibility of choosing axes in physics problems. Some have provided guidance on the importance of consistency in sign choice, while others are seeking clarification on how this affects the correctness of their answers.

Contextual Notes

There is an emphasis on the idea that different sign conventions can lead to answers that are mathematically correct but may differ in sign. The original poster expresses confusion about the implications of their sign choice compared to a reference solution.

Frankenstein19
Messages
56
Reaction score
0

Homework Statement


A 14.0kg bucket is lowered vertically by a rope in which there is 163N of tension at a given instant. What is the acceleration of the bucket.

Homework Equations


ƩF = may

The Attempt at a Solution


I know how to solve this but I got it wrong because of the signs.
Since the bucket was being lowered I thought that downward was going to be positive, but the correct solution says that up is positive; WHY?
 
Physics news on Phys.org
It doesn't matter what you choose to be positive or negative. If you chose differently than the book, then your signs will be opposite at the end. That's it. As long as you're consistent, it'll be the same.
 
axmls said:
It doesn't matter what you choose to be positive or negative. If you chose differently than the book, then your signs will be opposite at the end. That's it. As long as you're consistent, it'll be the same.
so even though its negative it's correct? or are you saying i wasnt consistent with my signs and that regardless of what i choose to be positive or negative that as long as I am consistent with it that i should get the correct answer?
 
If your answer is the negative of the correct answer, and you chose opposite axes as the correct answer, then your answer is also right. Yes, you can choose your positive direction to be whatever direction you want as long as it stays the same throughout the problem.

You'll get the correct answer for those axes. If you chose your positive direction to be the opposite direction as someone else, that just means your answer will be the negative of theirs.
 
  • Like
Likes   Reactions: Frankenstein19
axmls said:
If your answer is the negative of the correct answer, and you chose opposite axes as the correct answer, then your answer is also right. Yes, you can choose your positive direction to be whatever direction you want as long as it stays the same throughout the problem.

You'll get the correct answer for those axes. If you chose your positive direction to be the opposite direction as someone else, that just means your answer will be the negative of theirs.
ohh ok thank you so much!
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 9 ·
Replies
9
Views
9K
Replies
13
Views
5K
  • · Replies 15 ·
Replies
15
Views
3K
Replies
15
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 1 ·
Replies
1
Views
7K
Replies
11
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K