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# Centripetal force on particle by seat, what type is it? watch

1. The force on the particle, which keeps the particle moving in a horizontal circle, is exerted by the seat. Is this a reaction force or friction force, or what other type for that matter? Just couldn't figure out the type of force, can you explain what it would be, please

P.S. I am only concerned about the force acting on the particle sitting on the seat. The tension of the rope acts on the seat, so is irrelevant here.
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2. Friction on the seat keeps the particle in a circular path, and the tension in the rope keeps the seat in a circular path. (Horizontally anyway)
3. It's not clear from the diagram exactly what is happening, but the (centripetal) force of the seat on the particle would be a reaction type force. I'm not sure what the red arrow force represents, but this is not the centripetal force.
Furthermore, the rope would apply a force to the seat, enabling the seat to apply a force to the particle.
4. (Original post by Wesssty)
Wesssty
(Original post by Stonebridge)
stonebridge
I have made a little change in the diagram and added a P.S.
@wesssty: why is it called friction? I can imagine it like a restraining force, but it doesn't conform to my concept of friction. What type of force is exerted on you by a seatbelt when you brake, I wonder?
I have made a little change in the diagram and added a P.S.
@wesssty: why is it called friction? I can imagine it like a restraining force, but it doesn't conform to my concept of friction. What type of force is exerted on you by a seatbelt when you brake, I wonder?
In the car, its the reaction to your momentum into the seatbelt, its friction. The friction on the seat on the ride, acts as the centripetal force, always towards the centre of the circle.

Edit: In a test, don't say centripetal force, say friction. They'll bugger you for that.
6. Friction acts against momentum, yes? It does the same in both cases. If there were no friction on either the seat or seatbelt, you would slip straight out of it and be thrown to your death xD
7. The red arrow pointing inwards represents the centripetal force that keeps the seat going round in circle surely? The centripetal force is provided by the horizontal component of the tension. So this also acts on the particle to keep it moving in a circle.

(It could also be the normal reaction of the seat on the particle, which balances the particle's force on seat... but I'm not entirely sure how that would work...)

Sorry if i confused anyone, also sorry if i happen to be entirely wrong but I was taught centripetal force like this!
8. (Original post by Wesssty)
Friction acts against momentum, yes? It does the same in both cases. If there were no friction on either the seat or seatbelt, you would slip straight out of it and be thrown to your death xD
thnx
9. Ssadi. Part of the confusion here is that the question and diagram is not quite specific enough. What exactly is that force labelled with the red arrow?
The force on the particle will come from the two sides of the seat in contact with it.
The resultant force on the particle will be the vector sum of these two forces.
Depending on what that other force is, it also has a component in the direction of the centre of the circular motion, and can thus affect the forces due to the seat.
If the seat is allowed to rotate about its link with the rope, then you also have to take moments and rotation into account and will get a much more complex problem.
It would help to have a clearer description of the problem.
10. (Original post by Stonebridge)
Ssadi. Part of the confusion here is that the question and diagram is not quite specific enough. What exactly is that force labelled with the red arrow?
The force on the particle will come from the two sides of the seat in contact with it.
The resultant force on the particle will be the vector sum of these two forces.
Depending on what that other force is, it also has a component in the direction of the centre of the circular motion, and can thus affect the forces due to the seat.
If the seat is allowed to rotate about its link with the rope, then you also have to take moments and rotation into account and will get a much more complex problem.
It would help to have a clearer description of the problem.
The problem is:
A person is riding a swing carousel. What force causes him to move in the horizontal circle?
The problem is:
A person is riding a swing carousel. What force causes him to move in the horizontal circle?
centripetal.

you are thinking about the question too much
The problem is:
A person is riding a swing carousel. What force causes him to move in the horizontal circle?
It would have saved a lot of time if you had asked that at the start.

As the poster above says. Centripetal force.
13. The force that makes something move in a circular motion is always called the centripetal force. It's the resultant force acting on the particle in the direction towards the centre of circle. What provides the centripetal force is another question.
14. Thanks everyone

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