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- Thread starter goldfish9776
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as j dot j = 1 , so the product of j and j is only the scalar magnitude, with no unit ?j.j? You have to understand why, for each such unit vector, this dot product is 1. As a hint, take the definition of dot product.

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as j dot j = 1 , so the product of j and j is only the scalar magnitude, with no unit ?

##i,j,k## are all vectors, to be more precise they are orthonormal vectors, this means they are all perpendicular to each other and their magnitude is 1. It's useful to use combinations of these vectors to find any vector ##v## in R3 (3D).

e.g.: ##v = ai + bj + ck##

Where a,b,c are real numbers.

These vectors form an orthonormal basis in R3, but thats just a fancy term to say that these vectors can be combined to find ANY vector in 3D.

So, when you ask why ##j•j## has no unit, it makes no sense. The dot product gives a scalar;

##j•j = 1##

Since the magnitude of ##j## is 1.

- #6

SammyS

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The short answer is, Yes?as j dot j = 1 , so the product of j and j is only the scalar magnitude, with no unit ?

I assume you mean, no unit vector.

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