In the circular motion below, what will be the velocity?

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Homework Help Overview

The discussion revolves around a problem in circular motion, specifically focusing on the change in velocity when both initial and final velocities are given as 2 m/s. Participants are trying to clarify the relationship between velocity and acceleration in this context, while also addressing the clarity of accompanying diagrams.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are examining the calculation of change in velocity and questioning the interpretation of acceleration versus velocity. There is a focus on the vector nature of velocity and the implications of using unit vectors in the calculations. Some participants suggest that the problem needs to be restated for clarity.

Discussion Status

The discussion is ongoing, with participants providing feedback on the clarity of diagrams and the representation of vectors. There is no explicit consensus on the interpretation of the problem, but various perspectives are being explored regarding the calculations and assumptions made.

Contextual Notes

Some participants note that the provided diagrams are unclear, which may hinder understanding. There is also mention of the use of complex variables to represent vectors, raising questions about their appropriateness in this context.

HCverma
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Homework Statement


In circular motion what will be the change in velocity if initial velocity and final velocity is 2 m/s? From the left, in the 3rd diagram, if initial velocity and final velocity is 2 m/ s then what is the change in velocity? t = 5 s

Homework Equations

The Attempt at a Solution


the answer should be.
Acceleration = Vf - Vi / t = (-2i) - 2i / 5 = -4i / 5 = -0.8 m/s^2 but the answer is 0.8m/s^2.
 

Attachments

  • circular-motion-2-1024.jpg
    circular-motion-2-1024.jpg
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I see two illegible drawings (pure black) and something in the middle with some semi-legible chicken scratchings.
 
I think you should re-state the problem and provide readable drawing, it is not clear to me. Hint: velocity is a vector, giving value like "2 m/s" is not sufficient.
 
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HCverma said:

Homework Statement


In circular motion what will be the change in velocity if initial velocity and final velocity is 2 m/s? From the left, in the 3rd diagram, if initial velocity and final velocity is 2 m/ s then what is the change in velocity? t = 5 s

Homework Equations

The Attempt at a Solution


the answer should be.
Acceleration = Vf - Vi / t = (-2i) - 2i / 5 = -4i / 5 = -0.8 m/s^2 but the answer is 0.8m/s^2.
I have edited the image so that you can understand. Please see the image and let me know.
 

Attachments

  • circular-motion-2-1024.jpg
    circular-motion-2-1024.jpg
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HCverma said:
In circular motion what will be the change in velocity if initial velocity and final velocity is 2 m/s?
the answer should be.
Acceleration = Vf - Vi / t = (-2i) - 2i / 5 = -4i / 5 = -0.8 m/s^2 but the answer is 0.8m/s^2.
The question asks for a change in velocity but the answer is an acceleration? That's wrong.
 
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HCverma said:
(-2i) - 2i

How can both velocity vectors have same unit vector?

According to your drawing the first one, one is along j and another along i.

The pictures are still not clear. What are you using?
 
jbriggs444 said:
The question asks for a change in velocity but the answer is an acceleration? That's wrong.
Yes, my question is that in the picture change in velocity is 4 or -4, As I know the change in velocity is Vf -Vi = (-2i) - 2i = -4i. please see the picture.
 

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  • circular-motion-2-1024.jpg
    circular-motion-2-1024.jpg
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e-pie said:
How can both velocity vectors have same unit vector?

According to your drawing the first one, one is along j and another along i.

The pictures are still not clear. What are you using?
Could you suggest an online editor where I could sharpen my image as much clear as I can?
 
HCverma said:
Yes, my question is that in the picture change in velocity is 4 or -4, As I know the change in velocity is Vf -Vi = (-2i) - 2i = -4i. please see the picture.
I would say that the change in velocity is neither 4 nor -4. It is -4i.
 
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  • #10
jbriggs444 said:
I would say that the change in velocity is neither 4 nor -4. It is -4i.
would you please let me know whether you could understand my edited image I provided so that in future I would edit my images to that degree. Is it readable?
 

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  • circular-motion-2-1024.jpg
    circular-motion-2-1024.jpg
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  • #11
HCverma said:
would you please let me know whether you could understand my edited image I provided so that in future I would edit my images to that degree. Is it readable?
It is not pretty, but it is magnified enough that I can read it.
 
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  • #12
jbriggs444 said:
It is not pretty, but it is magnified enough that I can read it.
Ok, Thanks a lot for your kind reply.
 
  • #13
jbriggs444 said:
I would say that the change in velocity is neither 4 nor -4. It is -4i.
It is not clear to me whether the use of complex variables to represent the vectors comes from the original problem or has been introduced by the student.
@HCverma , please state the problem as given to you, word for word.
 
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  • #14
haruspex said:
It is not clear to me whether the use of complex variables to represent the vectors comes from the original problem or has been introduced by the student.
@HCverma , please state the problem as given to you, word for word.
Next time I will.
 
  • #15
HCverma said:
Next time I will.
Why not this time? As I understand it, you still lack an explanation for the book answer.
 
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