Problem in Vector Resolution and Component

1. May 14, 2013

avistein

I cannot understand what is vector resolution.It is said in the book that ON is the resolved part of A along X axis.It is also known as the x-component of A or the horizontal component of A.Ax may be regarded as the projection of A on X-axis. OM is the the resolved part of A along Y-axis.It is also known as the y-component of A or vertical component of A.The vertical component of A may be regarded as the projection of A on Y-axis.Now what is that projection? Is it the image of A on X-axis or Y axis?
Then why Ax+Ay=A and not A=Ax or A=Ay?If Ax and Ay are the images of A on X and Y resp. then the magnitude of Ax and Ay should be same as A,but no, why? Please explain me.I am very much confused.

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2. May 14, 2013

mathman

If A = (a,b), then the x axis projection is (a,0) while the y axis projection is (0,b).

It is quite simple - don't let the terminology confuse you.

3. May 14, 2013

deepani

vectors are simple

Don't get muddled up. Let, me explain what projection is. Say, the vector extends from (0,0) to (a.b). Suppose, you want projection on the x-axis, take a light source and place it directly above the end of the vector, the shadow would be at (a,0). Thus the projection of the vector extends from (0,0) to (a,0). similarly, y-component would extend from (0,0) to (0,b).
And, by the way Ax+Ay ≠ A. Using the Pythagoras theorem, (Ax)2+(Ay)2 = A2.
What the book might have meant would have been, was vector Ax+vector Ay = vector A. By writing vector, I am also considering the direction. While, above, I was only talking about magnitudes. With a little practice, you would easily understand the difference between the vector and it's magnitude. So, good luck!!