What is the scalar product V_1(DOT)V_2 ?

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Homework Help Overview

The discussion revolves around calculating the scalar product of two vectors, V_1 and V_2, with specific magnitudes and orientations in a three-dimensional space. V_1 is aligned with the z-axis, while V_2 lies in the xz-plane and makes a negative angle with the x-axis.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the usefulness of the scalar product equation and the need to find the components of each vector. Questions arise regarding how to determine the z-component of V_2 based on its angle and magnitude.

Discussion Status

Some participants have provided guidance on breaking down the vectors into their components, while others express uncertainty about the next steps. There is acknowledgment of the correct final answer by one participant, indicating some level of understanding has been achieved.

Contextual Notes

The original poster expresses uncertainty about the relevance of the equations provided and seeks clarification on the components of V_2, which suggests a need for further exploration of vector decomposition.

Rellsun
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Homework Statement



Vector V_1 points along the z axis and has magnitude V_1 = 80. Vector V_2 lies in the xz plane, has magnitude V_2 = 51, and makes a -49o angle with the x-axis (points below x axis)

Homework Equations



A.B=ABCos(theta)=AxBx+AyBy+AzBz

Cos(theta)=(AxBx+AyBy+AzBz)/AB

The Attempt at a Solution



im not really sure where to go from here I am not sure if those equations are useful
 
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The equations are indeed useful. Find the x,y and z components of each vector, then apply the first equation that you posted.
 
ok that helps a lot i don't know why i did do that. but how do you find the z component of the V_2=51?
 
Last edited:
Rellsun said:
Vector V_2 lies in the xz plane, has magnitude V_2 = 51, and makes a -49o angle with the x-axis (points below x axis)

Draw yourself two axes in the plane of the paper. Label the horizontal one x and the vertical one z (instead of the usual y). Draw the vector as indicated. Can you find its x and z components?
 
ahh thanks that makes much more sense. i got the final answer to be -3079.2 which is indeed correct. the help is appreciated.
 

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