Question

You are given a vector A = 125i and an unknown vector B that is perpendicular to A. The cross-product of these two vectors is A × B = 98k.
What is the y-component of vector B?

Answer 1

Answer:

  B_{y} = 0.784

Explanation:

The vector product of two vectors is

      A = Aₓ i ^ + $A_{y}$ j ^

      B = Bₓ i ^ + B_{y} j ^

the cross product is

    A xB = $\left[\begin{array}{ccc}i&j&k\\A_{x}&A_{y}&0\\B_{x}&B_{y}&0\end{array}\right]$

   A x B =i^   + j^    + k^ (Aₓ $B_{y}$ + A_{y} Bₓ)

     

is the result they give is

       A x B = 98 k ^

           

tells us that Aₓ = 125, we substitute

       98 = 125 B_{y} - Bₓ 0

       B_{y} = 98/125

       B_{y} = 0.784