What Is the Correct Theta to Use in Calculating the Scalar Product of Vectors?

AI Thread Summary
To calculate the scalar product of vectors, the angle θ used in the equation A·B = MagA × MagB × cos(θ) must be the angle between the two vectors. In this case, vector B has a known angle of 60°, while vector A's angle is unknown and should be designated as ψ. The angle for vector C is then ψ + 25°. To solve for the magnitude and direction of vector A, both the angle ψ and the magnitudes of vectors A and C must be determined. Understanding the correct angles is crucial for accurate calculations in vector analysis.
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Homework Statement



Let vectorB= 5.45 m at 60°. Let C have the same magnitude as A and a direction angle greater than that of A by 25°. Let B·A = 32.4 m2 and B·C = 35.1 m2. Find the magnitude and direction of A .

Homework Equations



A·B=MagAxMagBcosθ

The Attempt at a Solution


I just have one problem here. What do I use as theta? do i do cos 60?
magnitude of b is 5.45 and that of a is unknown but what about the angle?
thanks
 
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hi madinsane! :smile:
madinsane said:
What do I use as theta? do i do cos 60?
magnitude of b is 5.45 and that of a is unknown but what about the angle?

θ is the angle between the two vectors

you'll have to give the angle of A a name, ψ say, and then the angle of C is ψ + 25° :wink:
 
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