# Thread: Having trouble understanding a question - vector or scalar or neither

1. ## Having trouble understanding a question - vector or scalar or neither

Hey!
I am having trouble understanding what this question is answering, and also how to go about answering it! Hopefully some help can be derived from this thread.

Question
Explain where the quantity $\displaystyle \frac{a \bullet b + a \bullet a \times b}{|b|}$ is a vector, scalar, or neither. Explain your answer.

Solution
I don't understand what this question is asking. I know how to tell if something is a scalar or vector quantity (for example the wind blowing at 20km/h is scalar, but the wind blowing at 20km/h going NW is a vector) but I don't know how to apply it to this question!
I also know how to calculate the cross and dot products.

Thanks for your help!

2. Originally Posted by Kakariki
Hey!
I am having trouble understanding what this question is answering, and also how to go about answering it! Hopefully some help can be derived from this thread.

Question
Explain where the quantity $\displaystyle \frac{a \bullet b + a \bullet a \times b}{|b|}$ is a vector, scalar, or neither. Explain your answer.

Solution
I don't understand what this question is asking. I know how to tell if something is a scalar or vector quantity (for example the wind blowing at 20km/h is scalar, but the wind blowing at 20km/h going NW is a vector) but I don't know how to apply it to this question!
I also know how to calculate the cross and dot products.

Thanks for your help!
Use the fact that the dot product between two vectors produces a scalar quantity and that the cross product produces a perpendicular vector.

3. Originally Posted by Kakariki
Hey!
I am having trouble understanding what this question is answering, and also how to go about answering it! Hopefully some help can be derived from this thread.

Question
Explain where the quantity $\displaystyle \frac{a \bullet b + a \bullet a \times b}{|b|}$ is a vector, scalar, or neither. Explain your answer.

Solution
I don't understand what this question is asking. I know how to tell if something is a scalar or vector quantity (for example the wind blowing at 20km/h is scalar, but the wind blowing at 20km/h going NW is a vector) but I don't know how to apply it to this question!
I also know how to calculate the cross and dot products.

Thanks for your help!
It is kind of confusing, cause their use of "where" is kind of ambiguous, you would think they are maybe referring to the components. The components are familiar,so in the end you either get one or the other, area of a parallelepiped should should seal the deal.