Actually I have two questions(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

Vectors A and B are shown on the figure below. Which one of the

following statements is correct?

a) A . B = 0 and A × B ≠ 0

b) A . B ≠ 0 and A × B = 0

c) A . B ≠ 0 and A × B ≠ 0

d) A . B = 0 and A × B = 0

Picture: http://i.imgur.com/X0GB9.png

2. Relevant equations

A.B = AxBx + AyBy

3. The attempt at a solution

Obviously, the answer is zero. but the problem is the difference between A . B and A x B. I have long thought that those two are the same, but this question confused me.

I tried google for a bit and found out that [ dot product (u . v) gives a scalar ] and [ cross product (u x v) gives a pseudovector ]. It's my first time hearing about a pseudovector =_=

My second question is also about Vectors Multiplication

1. The problem statement, all variables and given/known data

A and B are the two vectors shown in the figure. Vector A is along the positive x

axis and has a magnitude of 5 cm, and the vector B is in the x-y plane at an angle 30º

with the positive x axis and has a magnitude of 4 cm. A × B =

a) 20 cm2 in the +x direction b) 10 cm2 in the +y direction

c) 10 cm2 in the +z direction d) 20 cm2 in the -y direction

2. Relevant equations

A.B = AxBx + AyBy

3. The attempt at a solution

When I tried to solve it I got C= 17.5 + 0, so the answer might be a.

This cm^2 and the +z confused me, so I just wanted to confirm.

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# Homework Help: Vectors Multiplication

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