Finding a Vector Perpendicular to One Vector and Parallel to Another

[nns91]

Homework Statement

Suppose n is normal to a plane and v is parallel to the plane. Describe how you would find a vector u that is both perpendicular to v and parallel to the plane.

Homework Equations

Cross product, dot product

The Attempt at a Solution

Since u is perpendicular to v, u dot v = 0. U is also parallel to the plane so u will be perpendicular to n, so u dot n=0.

How would I do the rest of it ?

 

[csprof2000]

Well, I can't give you the solution, but I will tell you that if I gave you a hint, you'd probably know it. Let's try.

You've used the dot product. Does the cross product help?

 

[Dick]

You didn't use the cross product. axb is perpendicular to both a and b, right?

 

[nns91]

Oh so u is basically n cross v ?

 

[Dick]

Oh so u is basically n cross v ?

Sure. Or any multiple thereof.