Position Vectors: Get Help & Understand Concepts

In summary, the conversation is about a student struggling to understand a concept in classical mechanics and seeking help from an expert. The topic involves graphing and visualizing angles between different axes and using formulas to transform between rectangular and polar coordinates. The expert provides hints and suggests following a book called Spiegel for further understanding. The conversation also includes a discussion about the correctness of the information given in a question and the student's confusion about the role of the z-axis in the concept.
  • #1
Erkan Tur
5
1

Homework Statement


upload_2015-12-9_18-29-34.png


Homework Equations


Relevant equations can be derived from the formulas, by exchanging x to v, v to a, etc.

The Attempt at a Solution


I've tried to graph them, but I am not able to visualize or understand them.

Please help me about these questions, I need some hints.

If you can suggest me some parts or questions relevant to this topic, I will be so happy because I cannot understand this concept.
 
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  • #2
Hi,

the info given in qn is not correct. here angle theta cannot be between r and z axis. as in that case theta becomes 90 degree and that doesn't make sense. theta is between r vector and x-axis and in that case it is just a transformation between rectangular and polar coordinates in 2-D. Please check attachment for your help. I guess you can try qn. c and qn. d now
.
UNW4Db049XQFCPf6TAy2g9H8.jpg
 
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Likes Erkan Tur
  • #3
Hello,
I was looking for it also, thank you for your kind reply and your work, I am trying to visualize the angle for the z axis, since there is no component for the z hat plane, it doesn't make sense thus it is 90 degrees. I agree with you, neverthless I told them this morning, but he told that there is more to think about that point. Thank you for your help, I understood your kind help correctly. Do you have any books in your mind, about the part of this classical mechanics?
 
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Likes Joydeep Munshi
  • #4
But if we neglect that z part and exchange with x hat, it is reasonable. Thank you anyway kind friend, I will be solving it as x
 
  • #5
Hi,

See if the angle is between Z axis and r vector than definitely r hat becomes y hat and theta hat becomes (-ve) x hat. from that perspective it is a rotation of the vector by 90 deg if you transform from rectangular to the r-theta co-ordinate.

You can follow Spiegel for concepts on Vectors and Curvilinear co ordinates.
 

FAQ: Position Vectors: Get Help & Understand Concepts

What is a position vector?

A position vector is a mathematical concept used to describe the position of a point or object in space. It is a directed line segment that starts at the origin and ends at the point or object in question.

How is a position vector represented?

A position vector is typically represented by the symbol r and is written in the form r = , where x, y, and z are the coordinates of the point or object in space.

What is the difference between a position vector and a displacement vector?

A position vector represents the location of a point or object in reference to the origin, while a displacement vector represents the change in position of the point or object from its initial position to its final position.

How is the magnitude of a position vector calculated?

The magnitude of a position vector is calculated using the Pythagorean theorem, which states that the magnitude is equal to the square root of the sum of the squares of its components. In other words, the magnitude of a position vector r = is given by |r| = √(x² + y² + z²).

How are position vectors used in physics?

In physics, position vectors are used to describe the location and movement of objects in space. They are an important part of vector calculus and are used in various equations and formulas to solve problems related to motion, forces, and energy.

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