If A 280i Bz 0 B 9886 and A times B 3640K determine the
     If A = 2.80i, B_z = 0, |B| = 9.886, and A times B = 3.640K, determine the x component of B. (Assume the x-component is positive.)_______ 
  
  Solution
A = 2.80 i
Let\'s assume
B = Bx i + By j + Bz k
Bz = 0
Now,
B = Bx i + By j
|B| = 9.886 = sqrt (Bx^2 + By^2)
Bx^2 + By^2 = 9.886^2
AxB = 3.640 k
AxB = (2.80 i)x(Bx i + By j) = 3.640 k
since, ixi = 0 and ixj = k
AxB = 2.8*By k = 3.640 k
By = 3.640/2.8 = 1.3 j
Bx^2 + By^2 = 9.886^2
Bx^2 + 1.3^2 = 9.886^2
Bx = sqrt (9.886^2 - 1.3^2)
Bx = 9.800 i
X-component of B = 9.800

