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## Homework Statement

1) Two men are near a hole, One man walks 12m east and then 12m North from a hole, the other walks 15m west and then 11m north, Find the dot product of their net displacements from the tree

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2) Vector A = -i +2j - 5k, Vector B = 3i +2j -2k

Find the magnitude and direction of the vector difference A -B

## Homework Equations

|A||B|cos(t) = A(x)B(x) + A(y)B(y) = |A||B|

## The Attempt at a Solution

1 )I didn't calculate the resultant as I think you don't need it, I used the components given

A = 12i + 12j

B = -15i +11j

|A||B| = (12*-15) + (12*11) = -48.

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2) A - B = -4i -3k

|A-B| = [itex]\sqrt{-4^2 + 0^2 + -3^2}[/itex] = 5.0

arctan([itex]\frac{0}{-4}[/itex] = 0

So the magnitude is 5.0 and the angle is 0 degrees? This seems wrong to me..

If anyone can tell me if I did these right or give me a tip in the right direction, it'd be very much appreciated. Thanks in advance