Cross Product Help: Homework Statement

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SUMMARY

The discussion centers on calculating the vector product of two vectors A⃗ = 4i + 7j and B⃗ = 5i − 2j. The correct vector product A⃗ × B⃗ is -43k, as the z-component is derived from the cross product calculation. The confusion arose from the online assignment system's feedback, which incorrectly suggested that the answer should not include i, j, and k, despite the correct answer being -43k. Participants confirmed that the initial calculation was accurate, highlighting the importance of understanding the representation of vector products.

PREREQUISITES
  • Understanding of vector operations, specifically cross products
  • Familiarity with unit vectors i, j, and k
  • Basic knowledge of vector notation and components
  • Experience with online assignment systems and their feedback mechanisms
NEXT STEPS
  • Review the mathematical principles of vector cross products
  • Practice calculating vector products using different vector pairs
  • Explore the implications of vector components in 3D space
  • Investigate common pitfalls in online math assignments and how to address them
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Students studying physics or mathematics, particularly those learning about vector operations and cross products, as well as educators looking to clarify common misconceptions in vector calculations.

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Homework Statement



Given two vectors A⃗ = 4i + 7j and B⃗ = 5i − 2j , find the vector product A⃗ × B⃗ (expressed in unit vectors).
Express your answer in terms of the unit vectors i, j, and k.

Homework Equations





The Attempt at a Solution



I know how to cross and multiply them but they don't give the z component so I assumed it was zero

This is what I got

0i + 0j - 43k

Why is that wrong ?, I'm doing this online assignment and it keeps telling me, "The correct answer does not depend on i,j and k"
 
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TheRedDevil18 said:

Homework Statement



Given two vectors A⃗ = 4i + 7j and B⃗ = 5i − 2j , find the vector product A⃗ × B⃗ (expressed in unit vectors).
Express your answer in terms of the unit vectors i, j, and k.

Homework Equations





The Attempt at a Solution



I know how to cross and multiply them but they don't give the z component so I assumed it was zero

This is what I got

0i + 0j - 43k

Why is that wrong ?, I'm doing this online assignment and it keeps telling me, "The correct answer does not depend on i,j and k"
You did it right. They probably just want -43k.

Chet
 
Chestermiller said:
You did it right. They probably just want -43k.

Chet

Yeah, I guess they just wanted -43k with the hat on top. Stupid system, now I lost 3% for each "wrong" attempt :mad:

Thanks for your reply
 

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