Y-component of Vector A if Vectors A and B are Orthogonal Date of Exam November 2016 Subject Mathematics, Surveying and Transportation Engineering Problem Compute the value of b if A and B are orthogonal. $${\bf A} = 2{\bf i} + b{\bf j} + {\bf k}$$ $${\bf B} = 4{\bf i} - 2{\bf j} - 2{\bf k}$$ A. 6 C. 4 B. 5 D. 3 Answer Key Click here to show or hide the Answer Key [ D ] Solution Click here to expand or collapse this section Orthogonal means perpendicular. For perpendicular vectors, their dot product is zero. ${\bf A} \cdot {\bf B} = 0$ $2(4) + b(-2) + 1(-2) = 0$ $2b = 6$ $b = 3$ ← Answer: [ D ] Category Advance Engineering Mathematics Engineering Mechanics Vectors Dot Product of Vectors Orthogonal Vectors Perpendicular Vectors Log in or register to post comments