Direction of Tension: FBD Down vs Up

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The discussion focuses on the direction of tension in a wire as represented in free body diagrams (FBD). It highlights that the tension direction is dependent on which end of the wire is being analyzed, with one end showing tension pulling downward and the other upward. A practical example illustrates this by describing two people pulling on opposite ends of a wire, demonstrating that each end experiences tension in opposite directions. The conversation emphasizes the importance of understanding the context of the forces acting on each end of the wire. Clarifying these concepts is crucial for accurately interpreting free body diagrams in physics.
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Homework Statement


why i figure b , the direction of FBD is in downward direction , whereas in a , its in upward directon

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Because in the two figures, you are looking at the opposite ends of the wire.
 
DEvens said:
Because in the two figures, you are looking at the opposite ends of the wire.
can you expalin further ?
 
werson tan said:
can you expalin further ?

Sure. Suppose we are each holding one end of a wire, and pulling as hard as we can. I am pulling to the left, say, and you to the right. So the wire is pulling me one way at my end. And the other end of the same wire is pulling you the exact opposite way at the other end.
 
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