Why does tension act downward in this problem?

[werson tan]

Homework Statement

how to determine the direction of tension ? why it acted in downward direction ? wy not in upward direction ?

Homework Equations

The Attempt at a Solution

 

[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.

 

[werson tan]

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.

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

 

[haruspex]

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

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

 

[werson tan]

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

why they will act downward on the junction B.

 

[haruspex]

why they will act downward on the junction B.

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?

 

[werson tan]

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?

yes

 

[werson tan]

yes

tats how the direction of tension it is ?

 

[haruspex]

yes

Yes which, down or up