# Doubt in uniform circular motion

1. Aug 21, 2013

### manimaran1605

why are we considering speed is constant to find velocity a particle in uniform circular motion, is it possible for a particle in a circular motion to have constant velocity?

2. Aug 21, 2013

### ZapperZ

Staff Emeritus
That doesn't make much sense, doesn't it?

BY DEFINITION, velocity is a vector, and circular motion involves something moving in a circle, i.e. CHANGING its direction all the time.

Zz.

3. Aug 21, 2013

### arildno

The velocity in circular motion is necessarily everchanging, the speed need not be, and might well remain constant.

4. Aug 21, 2013

### technician

STOP SHOUTING !,! Makes my eyes ache. :)
Motion in a helical path might interest you, this could be a combination of circular motion....where you have constant speed but changing velocity because of the changing direction. You could also have the circle moving at constant velocity to trace out the helix. This sort of 'circular' motion is common with electron beams.

5. Aug 22, 2013

### bobydbcn

by use of natural coordinates, it is very easy to prove that with constant speed and a fixed non-zero acceleration, the particle's motion must be circle. Moreover, if the particle's acceleration is zero, its trajectory is a straight line. I am a college teacher, believe in me.