# Circular Motion of a wire on a plane

1. Oct 29, 2007

### atavistic

What is the direction of normal force when a particle is moving in a wire fixed to a vertical plane or when it is moving on a sphere.I have seen in places when the normal force is sometimes towards the centre and sometimes it is away from the centre.Confused :S

2. Oct 29, 2007

### CompuChip

The particle is accelerated inward (always) in a circular motion. The normal force would then be outward (otherwise, the particle would go through the surface of the sphere is moving on).

3. Oct 29, 2007

### atavistic

BUt here are 2 questions which are contradictory :

1)A bead moves on a circular wire of radius r,fixed in a vertical plane,and there is no friction.The speed of the bead when it is at lowest point of the wire is u.Find the horizontal component of the acceleration of the bead(measured in the direction of u).

2)A cylindrical bucket filled with water is whirled around in a vertical circle of radius r.What can be the minimum speed at the top of the path if water does not fall out from the bucket ?If it continues with this speed ,what normal contact force the bucket exerts on water at the lowest point of the path?

IN the solution of the first question,the N force is taken inwards and in the second question,at the top most point N is taken inwards but at the lowest point it is taken upwards.Confused :S