# The angle between P and Q?

1. Jul 13, 2018

### Indranil

• Member has been warned for showing no own effort.
1. The problem statement, all variables and given/known data
The resultant R of vectors P and Q is perpendicular to P and R=P both, then the angle between P and Q is what?
Now, what is the concept behind it? Could you provide me with an image of the resultant perpendicular to two vectors so that I can understand the concept and start solving the problem?

2. Relevant equations

3. The attempt at a solution

2. Jul 13, 2018

### stevendaryl

Staff Emeritus
What do you mean by "is perpendicular to P and R=P both"? I don't know how to parse that.

3. Jul 13, 2018

### Indranil

nither I understand what it means. The question says like this.

4. Jul 13, 2018

### mjc123

Perhaps it means "R is perpendicular to P and |R| = |P|". Or perhaps "R is perpendicular to P and R = P". Or whatever notation. That is, the vector R is at right angles to the vector P, and the length of R equals the length of P.

5. Jul 13, 2018

### stockzahn

I agree with stevendaryl, the question is not easy to understand formulated like this, but here is my guess:

The resultant vector $\vec{R}$ is the sum of the two vectors $\vec P$ and $\vec Q$. You know the direction and the length of $\vec P$, where the latter is identical with the length of $\vec R$. Therefore you know the lengths of two vectors and their angle with respect to each other. By drawing this constellation, there is only one possibility for $\vec Q$ to fit between them. Try to draw it, show your attempt and it's easier to help you.

6. Jul 13, 2018

### Staff: Mentor

Please report to the mentors those cases, in which the OP doesn't show any effort to tackle his problem, instead of answering it. If you think it is a general problem of understanding rather than a homework problem, then please also report it, such that we can move it to a technical forum.

@Indranil : If you're in doubt what to do, you can always ask in advance for guidance by a mentor, or report your own post to be evaluated.