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Dot product

1. Homework Statement
Vector A has a magnitude of 5.00 units, and vector B has a magnitude of 9.00 units. The two vectors make an angle of 49° with each other. Find (vector A)(vector B)


2. Homework Equations



3. The Attempt at a Solution

(5i+0j)(0i+9j)=
(5N)(0m)+(0N)(9m)=

square root (5^2+0^2)
=5N

Could someone please tell me if this is correct and if not could someone show me how to do it?

Thank you very much
 

Answers and Replies

Shooting Star
Homework Helper
1,975
4
Find (vector A)(vector B)
(vector A)(vector B)?

This notation does not mean anything. Possibly, you mean the scalar product A.B?

How did you utilize the 49 deg given in the problem?

A.B = (magnitude A)(magnitude B)cos [itex]\theta[/itex], where [itex]\theta[/itex] is the angle between A and B.

Take my advice given in the other post.
 
Thank you

Regards
 

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