- #1
Why is the reaction force in this direction?
- Thread starter Neon32
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In summary, the direction of the reaction force for the short cable and link cable is determined by taking moments about one of the pinned ends. The resultant moment must be zero, which leads to a certain ratio of the force components along the coordinate axes (Fx/Fy). This explains why the reaction force appears to be in the opposite direction when viewed from the perspective of the bar or the rope/link.
- #2
Bystander
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"Why?" Consider the resultant(s) for other directions.
- #3
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From the point of view of the bar, something (the rope or link) is pulling it in that direction.
If you would analyze it from the rope or link point of view, the bar would be pulling on it and, thus, the direction would be in reverse.
Imagine yourself in tug of war, Who is pulling on the rope? From each team's point of view, it is the other team.
If you would analyze it from the rope or link point of view, the bar would be pulling on it and, thus, the direction would be in reverse.
Imagine yourself in tug of war, Who is pulling on the rope? From each team's point of view, it is the other team.
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CWatters
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It's easy to understand the case with a rope... It can only provide a force in the same direction as the rope. It's less obvious with the short link but the answer is the pins at the end. Because both ends have pins the link cannot transmit a force in any other direction.
- #5
Randy Beikmann
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Neon32, it should help to take moments about one of the two ends, which are both pinned. The resultant moment must be zero, and that requires a certain ratio of the force components along the coordinate axes (Fx/Fy). That determines the direction of the resultant force.
FAQ: Why is the reaction force in this direction?
1. Why is the reaction force in the opposite direction of an applied force?
The reaction force is in the opposite direction of an applied force because of Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. When a force is applied to an object, the object exerts an equal and opposite force in the opposite direction.
2. Can the direction of the reaction force change?
Yes, the direction of the reaction force can change depending on the direction of the applied force. If the applied force changes direction, the reaction force will also change direction to remain in the opposite direction.
3. Why is the reaction force equal in magnitude to the applied force?
The reaction force is equal in magnitude to the applied force because of Newton's third law of motion. The force applied by one object on another object is always equal in magnitude and opposite in direction.
4. Does the reaction force always act on the same object as the applied force?
No, the reaction force can act on a different object than the applied force. For example, when you push against a wall, the wall exerts a reaction force on you, but the applied force is not acting on the wall.
5. Can the reaction force be greater or smaller than the applied force?
The reaction force can be greater or smaller than the applied force, depending on the situation. If the applied force is greater than the opposing forces, the reaction force will be smaller. If the applied force is smaller than the opposing forces, the reaction force will be greater.