Physics C summer assignment help-vectors

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1

<p>Unfortunately for me, I can't seem to figure out this vector problem in my Physics C summer assignment. I'm hoping that someone here, with better talents in math than any I will ever have, could help me. =]</p>

<p>Basically, it asks to find the vector product of A times B, expressed in units vectors.
A= 4.00i + 3.00j<br>
B = 5.00i - 2.00 j
And also find the magnitude of the vector product. </p>

<p>I always seem to have trouble finding the vector product. Scalar [dot] products never irk me though. </p>

<p>If someone knows how to figure this one out, could you please post the steps to how you found it?</p>

2

<p>The vector (cross) product of A and B is the determinant of the 3x3 matrix which has as its first row, i j k. Second row, 4 3 0 (that's vector A, which has no k component). Third row, 5 -2 0 (vector B). The determinant is 0i - 0j +(-8-15)k which is -23k. So AxB = -23k, and its magnitude is 23.</p>

3

<p>how did you determine that the determinant was 0i - 0j +(-8-15)k? I know how to put it into the calculator and such, but... =/</p>

4

<p><a href="http://mathworld.wolfram.com/CrossProduct.html%5B/url%5D"&gt;http://mathworld.wolfram.com/CrossProduct.html&lt;/a>
Read this about Cross Products</p>

<p><a href="http://mathworld.wolfram.com/Determinant.html%5B/url%5D"&gt;http://mathworld.wolfram.com/Determinant.html&lt;/a>
Read this about Determinants</p>

<p>Look through a linear algebra book..</p>

5

<p>Hey, thanks. I actually did learn determinants this past year in PreCal, but I guess I forgot a lot of it. =/ [not good at all]</p>