Three non-zero vectors satisfy A+B+C=0 with |A|=3, |B|=4 and |C|=5. Which set correctly gives A·B, |A×B|, the angle between A and B, and A·(B×C)?
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Question

Three non-zero vectors satisfy A+B+C=0 with |A|=3, |B|=4 and |C|=5. Which set correctly gives A·B, |A×B|, the angle between A and B, and A·(B×C)?

G1 Physics · Accepted Answer

Since C=−(A+B), 25=9+16+2A·B, so A·B=0 and θ=90°. Cross magnitude=3×4=12. Also C lies in the plane of A and B, so scalar triple product=0.