# The angle between P and Q?

• Indranil

#### Indranil

Member has been warned for showing no own effort.

## Homework Statement

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?

## The Attempt at a Solution

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

What do you mean by "is perpendicular to P and R=P both"? I don't know how to parse that.
nither I understand what it means. The question says like this.

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.

## Homework Statement

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?

## The Attempt at a Solution

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.

• stevendaryl
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.