Three vectors A, B, and C add together to yield zero

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Three vectors A, B, and C sum to zero, with A and C pointing in opposite directions, and A's magnitude being twice that of C (A = 2C). The discussion explores the implications of these relationships to determine the correct conclusion about the vectors. The user attempts to substitute values for A, B, and C but struggles with the calculations. They recognize that A can be expressed as -2C, leading to a simplified equation involving B and C. Clarification is sought on how to derive the correct relationships among the vectors based on the given conditions.
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Homework Statement



Three vectors A, B, and C add together to yield zero: A + B + C = 0. The vectors A and C point in opposite directions and their magnitudes are related by the expression: A = 2C. Which one of the following conclusions is correct.

A. B and C have equal magnitudes and point in the same direction.
B. A and B have equal magnitudes and point in opposite directions.
C. B and C have equal magnitudes and point in opposite directions.
D. A and B point in the same direction, but A has twice the magnitude of B.
E. B and C point in the same direction, but C has twice the magnitude of B.


Homework Equations



A + B + C = 0

A = 2C

The Attempt at a Solution



I've never been good at these types of problems. They feel like brain teasers. I was thinking about replacing A, B, and C with numbers. A being equal to 2 times C. But that didn't work out as smoothly as I had hoped.

Um...help, please?
 
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A points in the opposite direction of C, so there is a negative involved: A = -2C.
With this, you can view it as
-2C + B + C = 0 ... (1)
-C + B = B - C = 0 ... (2)
Now you just have to figure out what set of vectors for B satisfy expression (2).
 
Sorry, I'm still not following...

Expression (1) makes sense, but (2) doesn't...
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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