# Homework Help: Direction of tension of metal rod

1. Oct 19, 2015

### werson tan

1. The problem statement, all variables and given/known data
the metal rod is supported by another metal rod at one end . The metal rod is supported by another metal rod at the end. so , the direction of tension of metal rod is acted upward , right ?( this is the initial prediction) But , i was told that the tension that we get from calculation will always be acted downwards , which is correct ?

2. Relevant equations

3. The attempt at a solution

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2. Oct 19, 2015

### PhanthomJay

Your diagrams on this and prior posts make no sense whatsoever. If you are wondering about the direction of tension forces , they always are pulling forces, not pushing forces. So if a rope or tension member pulls upward on a pin support, the pin support must pull downward on that rope or member, per Newton 3rd law.

3. Oct 19, 2015

### werson tan

Yes, I am thinking about the direction of tension of rope /metal rod. So in both cases that I asked earlier, the direction of tension of metal rod / rope should be in doenward direction, as opposed to the pin support that push against the metal rod / rope (in

4. Oct 19, 2015

### werson tan

Yes, I am thinking about the direction of tension of rope or metal rod. So, the direction of tension of rope/metal rod will always be in the downward direction as in the both cases I have asked earlier? This is becoz of the pin support pull against the rope/ metal rod?(in upward direction) So, the reaction of this (tension of rope/ metal rod) will acts in downward direction?

5. Oct 20, 2015

### PhanthomJay

6. Oct 20, 2015

### werson tan

?

7. Oct 20, 2015

### PhanthomJay

Suppose you fasten a rope to a support on the floor. Then you pull upward on the rope to place it in tension. At the top of the rope, your hand exerts an upward force on the rope, and the rope exerts a downward force on your hand. At the bottom of the rope, the rope exerts an upward force on the support, and the support exerts a downward force ( the so called reaction force) on the rope.