- #1
Adesh
- 735
- 191
Situation: Let’s say we have a wire bent into a circular shape, there lies a bead through the wire and it can slide through it. The wire is kept in vertical plane and is swung along the axis AB.
My question : How the centripetal force is provided to the bead?
The bead will go into a circular motion as well (the wire is being swung in the vertical plane) and force acting on the bead are : gravity, and centripetal force. By help of Perok and haruspex, I know that centripetal force is just a component of forces (like tension, normal) it’s not something which exists on its own.
When we tie a stone to the rope and swing it round the circle in a horizontal plane, it is the tension force which is causing the centripetal acceleration (acceleration towards the center) and this tension exists because we are pulling the stone towards us, hence it’s we who are actually doing the real work.
But in the situation that I have described at first, I cannot seem to imagine how the centripetal force will ever come into play. How swinging around AB would provide the the centripetal force to the bead? Will there be some stretches or starins? Some people are saying that there are two forces acting on the bead when it swung: gravity and normal force from the wire, and it’s the horizontal component of the normal force which is causing the centripetal acceleration. What I don’t understand is why the wire would push the bead normally at all? (Well, I know why it cannot push tangentially, because we have assumed the wire to be friction-less hence all the forces from the wire will be perpendicular to it) but why wire will push the bead normally? What causes it to push on the bead? A mere contact cannot produce a normal force, we have to have something more because two pens touching each other on my desk aren’t pushing on each other apart until I push them together.
I hope I made myself clear, I tried my best to explain myself.
My question : How the centripetal force is provided to the bead?
The bead will go into a circular motion as well (the wire is being swung in the vertical plane) and force acting on the bead are : gravity, and centripetal force. By help of Perok and haruspex, I know that centripetal force is just a component of forces (like tension, normal) it’s not something which exists on its own.
When we tie a stone to the rope and swing it round the circle in a horizontal plane, it is the tension force which is causing the centripetal acceleration (acceleration towards the center) and this tension exists because we are pulling the stone towards us, hence it’s we who are actually doing the real work.
But in the situation that I have described at first, I cannot seem to imagine how the centripetal force will ever come into play. How swinging around AB would provide the the centripetal force to the bead? Will there be some stretches or starins? Some people are saying that there are two forces acting on the bead when it swung: gravity and normal force from the wire, and it’s the horizontal component of the normal force which is causing the centripetal acceleration. What I don’t understand is why the wire would push the bead normally at all? (Well, I know why it cannot push tangentially, because we have assumed the wire to be friction-less hence all the forces from the wire will be perpendicular to it) but why wire will push the bead normally? What causes it to push on the bead? A mere contact cannot produce a normal force, we have to have something more because two pens touching each other on my desk aren’t pushing on each other apart until I push them together.
I hope I made myself clear, I tried my best to explain myself.