# What is the direction of the Reaction force

• Victorian91
In summary: Sometimes the reaction force is stronger and sometimes the weight is stronger. But the direction of the reaction force is always the same, no matter what the weight or reaction is.
Victorian91
Hey I am confused about the direction of reaction force..

When a ball is on a vertical track at the bottom most of the track,
I understand that the reaction is opposite the weight of the ball, mg.

But when it is directly above the vertical track the reaction force is towards the center, same direction as the weight of the ball.

That means that the reaction force is not always opposing the weight?

I think that the reaction force exists so that the object won't sink in the track..
that is why at the bottom of the track, it points upwards..
At above the track, it points downwards, so that the object won't sink in the track..
Any other explanations.

That is what I think..
Thanks

What's the geometry of this "vertical track". I'm not quite getting it. Am i alone?

Victorian91 said:
Hey I am confused about the direction of reaction force..

When a ball is on a vertical track at the bottom most of the track,
I understand that the reaction is opposite the weight of the ball, mg.

But when it is directly above the vertical track the reaction force is towards the center, same direction as the weight of the ball.
Can we assume that you are talking about a ball rolling on the inside of a vertical circular track? If so, then since the ball executes circular motion it must have an acceleration component towards the center of the circle. Which means that at the top of the motion, the net force must be downward (towards the center). That net force is the sum of the reaction force and the weight, both of which act downward.

At the bottom of the motion, the net force must be upward (towards the center). That means that the reaction force must act upward to counteract the downward weight and provide the centripetal force.

That means that the reaction force is not always opposing the weight?
Correct. It's not.

## What is the direction of the Reaction force?

The direction of the reaction force is dependent on the direction of the applied force. According to Newton's third law of motion, the reaction force will always act in the opposite direction of the applied force.

## Does the direction of the Reaction force change?

The direction of the reaction force will change if the direction of the applied force changes. However, the reaction force will always act in the opposite direction of the applied force.

## How is the direction of the Reaction force determined?

The direction of the reaction force is determined by the direction of the applied force. The reaction force will always act in the opposite direction of the applied force, as stated by Newton's third law of motion.

## Can the direction of the Reaction force be manipulated?

The direction of the reaction force cannot be manipulated as it is a natural result of Newton's third law of motion. However, the magnitude of the reaction force can be altered by changing the magnitude of the applied force.

## Why is the direction of the Reaction force important to understand?

The direction of the reaction force is important to understand as it helps to determine the overall motion and equilibrium of an object. Knowing the direction of the reaction force allows scientists to accurately calculate and predict the motion and stability of a system.

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