# Direction of tension

1. Oct 16, 2015

### werson tan

1. The problem statement, all variables and given/known data
how to determine the direction of tension ? why it acted in downward direction ? wy not in upward direction ?

2. Relevant equations

3. The attempt at a solution

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2. Oct 16, 2015

### haruspex

Tension and compression are better regarded as pairs of opposite forces rather than as a single force. Which way they act depends on your standpoint. If you pull on a rope, you feel as though the tension is pulling you, but the rope feels as though both ends are pulling on it.

3. Oct 16, 2015

### werson tan

well, i still dotn understand , can you explain based on the question ?

4. Oct 16, 2015

### haruspex

The tensions in BC, BD act upward on the girder at C and D but downward on the junction B.

5. Oct 16, 2015

### werson tan

why they will act downward on the junction B.

6. Oct 16, 2015

### haruspex

Imagine yourself as junction B, i.e. you are holding the two wires BC and BD, and holding a third wire going up to some support above you. You alone are holding it all together. Are the wires BC and BD pulling you down or pushing you up?

7. Oct 16, 2015

### werson tan

yes

8. Oct 16, 2015

### werson tan

tats how the direction of tension it is ?

9. Oct 16, 2015

### haruspex

Yes which, down or up