Calculate angles from axis with a 3d vector

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Homework Help Overview

The problem involves calculating the magnitude of a 3D vector and determining the angles between the vector and the x, y, and z axes. The vector is given in component form, and there is uncertainty about the application of the dot product in this context.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the magnitude of the vector and its components in various planes. There is confusion regarding the relationship between vector notation and scalar magnitude, particularly in the context of the dot product. Some participants express uncertainty about how to proceed with the problem, especially regarding the dot product and its relevance.

Discussion Status

The discussion is ongoing, with participants seeking clarification on the dot product and its application to find angles. Some have attempted calculations for the vector's magnitude but are unsure about the next steps. There is a request for assistance due to a lack of prior instruction on the necessary concepts.

Contextual Notes

Participants note that the relevant concepts, such as the dot product, were not covered in their coursework, leading to confusion about how to apply them to the problem. There is a time constraint mentioned, as the problem needs to be resolved by the next day.

xX1SHOt
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Homework Statement



A vector is given by R(vector) = 1.90 ihat + 1.30 jhat + 2.92 khat.

Find the magnitude of the vector

Find the angle between the vector and the x, y, and z axis

Homework Equations



I have read something about dot product but I am not sure if it applies here

The Attempt at a Solution



R(magnitude)=3.7183867

R(magnitude in xy plane)=2.302

R(magnitude in yz plane)=3.196

R(magnitude in xz plane)=3.484

I don't know if I should have solved for these or if i should try to solve for the angles in each plane specifically. I was just getting numbers to see where it got me.
 
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Remember that for dot products
[tex] \vec{u}\cdot\vec{v} = |u||v|\cos{\theta}[/tex]

Where theta is the angle between the vectors. So choose u = your vector R, and v = ihat, and you get the angle between R and the x-axis.
 
arent v(vector) and v(magnitude the same which follows for u. which means that it would just be cos( 0 ) b/c that is one
 
xX1SHOt said:
arent v(vector) and v(magnitude the same which follows for u. which means that it would just be cos( 0 ) b/c that is one
Are you asking if [itex]\vec{v}[/itex] and [itex]|v|[/itex] (to use nicksauce's notation) are the same? They're not... [itex]\vec{v}[/itex] is a vector, while [itex]|v|[/itex] is a scalar. Completely different things. It's like the difference between an arrow and the length of the arrow.

Do you know how to take the dot product of two vectors?
 
no that's what I am basically asking, we were not taught this but need to know it i guess to do this problem. Also it is not anywhere in the chapter's we are studying
 
I have to figure this out by tomorrow and i can't really figure out how to do it from looking up up anywhere. Can someone please resolve this one before it is due tomorrow?
 

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