If the dot product of two non-zero vectors A and B is zero, their cross product will be of magnitude:
Correct answer: D. AB
- A. AB sin θ
- B. B cos θ
- C. AB sin6 θ
- D. AB
Explanation
If the dot product of two non-zero vectors A and B is zero, their cross product will indeed be of magnitude AB. The dot product of two vectors A and B is given by the formula A · B = |A| |B| cos θ, where |A| represents the magnitude of vector A, |B| represents the magnitude of vector B, and θ represents the angle between vectors A and B. If the dot product of A and B is zero, it means that A · B = 0. Rearranging the formula, we get |A| |B| cos θ = 0. Now, let's consider the cross product of A and B, denoted as A x B. The magnitude of the cross product is given by |A x B| = |A| |B| sin θ, where sin θ represents the sine of the angle between vectors A and B. Since the dot product of A and B is zero, we can conclude that cos θ = 0. This implies that the angle θ between A and B is 90°, making them perpendicular to each other. In this case, sin θ = 1, because the sine of 90° is 1. Therefore, |A x B| = |A| |B| sin θ = |A| |B| * 1 = |A| |B| = AB. So, if the dot product of two non-zero vectors A and B is zero, their cross product will be of magnitude AB.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Vectors and Equilibrium
Vectors have magnitude and direction, unlike scalars, and are combined by head-to-tail or parallelogram methods. Work covers rectangular components, equilibrium when the resultant force is zero, the scalar product for work and projections, and the vector product for torque and cross-product direction using the right-hand rule.
Practise Vectors and Equilibrium
431 free Vectors and Equilibrium MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Vectors and Equilibrium questions
The magnitude of.....
The cross product of two parallel vectors A and B (i.e. A x B) is equal to:
The scalar product of two vectors is negative when:
The y-component of a vector 100N force, making an angle of 30° with the x-axis is:
The magnitude of cross product of two parallel vectors a and b is equal to:
Two vectors of magnitude A1 and A2 inclined at each other at an angle θ have resultant of magnitude equal to: