How to represent this statement in a diagram?

[Benjamin_harsh]

Homework Statement

How to represent this statement in a diagram?

Relevant Equations

How to represent this statement in a diagram?

Statement: My friend represented this sentence "Two forces have magnitude of 3N and 5N, and have an angle of 60 between them" into this diagram:

But why didn't he represent like this?:

 

[BvU]

Hi,

You can't tell until you add arrowheads. If A and B both point to the left in the first diagram (or both to the right), the angle is indeed 60 degrees.
And if e.g. A points to the left and B to the right, then the smallest angle to rotate A to make it align with B is 120 degrees.

 

[Benjamin_harsh]

Hi, You can't ...rees.

See, I made changes to my diagrams.

 

[BvU]

Yes, now my #2 post looks weird...

Never mind. The smallest angle you can rotate over to make them align and pointing in the same direction is 120 degrees in the top picture and 60 in the lower.

 

[Benjamin_harsh]

smallest angle you can rotate over to make them align and pointing in the same direction is 120 degrees in the top picture and 60 in the lower.

So both diagrams are fits the context ?

 

[BvU]

No. In the top diagram the angle between the two vectors is 120 degrees, not 60.

 

[Benjamin_harsh]

In the top diagram the angle between the two vectors is 120 degrees, not 60.

Are you saying second diagram is correct ?

 

[BvU]

What I say isn't important; what you understand is

In the bottom diagram the angle between the two vectors is 60 degrees

 

[Orodruin]

But why didn't he represent like this?

The short answer is: Because he was wrong.

 

[Benjamin_harsh]

The short answer is: Because he was wrong.

Thank you

 

[BvU]

@Benjamin_harsh : it it clear to you now, and can you explain (e.g to your friend) why he was wrong ?

 

[Benjamin_harsh]

@Benjamin_harsh : it it clear to you now, and can you explain (e.g to your friend) why he was wrong ?

YES, I will explain to him.