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Vigorous
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Suppose a particle is moving around a circular track of radius R at speed v. To bend around a circle some agency has to exert an acceleration towards the center of the circle. I analyze the forces acting on the particle, its weight and the normal force and there is no acceleration in the vertical direction. Why is it the friction of the circular track that provides the centripetal acceleration?
static friction- is whatever force required to keep the object from moving and is always directed opposite to the velocity of the moving particle.
Accordingly, for a particle in circular motion, friction would be directed opposite velocity vector (tangential). I also thought about it in another way, the particle has an inertia to continue its linear motion and not follow a circular path, so to maintain a constant speed, friction acts in the radial direction to keep the velocity magnitude constant along the circle at all times and by this reasoning the speed is constant. But why should friction act this way and not act as I talked earlier opposite to the velocity vector?
static friction- is whatever force required to keep the object from moving and is always directed opposite to the velocity of the moving particle.
Accordingly, for a particle in circular motion, friction would be directed opposite velocity vector (tangential). I also thought about it in another way, the particle has an inertia to continue its linear motion and not follow a circular path, so to maintain a constant speed, friction acts in the radial direction to keep the velocity magnitude constant along the circle at all times and by this reasoning the speed is constant. But why should friction act this way and not act as I talked earlier opposite to the velocity vector?
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