# Acceleration in Circular Motion

1. Apr 11, 2014

### Emz19

Could anyone help my with proving that the acceleration of an object that is moving with uniform circular motion is directed towards the centre of the circle and is of magnitude ω^2(r). Thanks

2. Apr 11, 2014

### Naz93

Directed towards centre because motion is uniform, so speed constant, which means no force in direction of motion. Has to be in not out in order to "push" the object round in a circle.

For the magnitude... try drawing a vector triangle showing the change in velocity for a small distance moved around the circle - the 3 sides of the triangle being the initial velocity, the final velocity (the velocity after moving a small distance around), and the change in the velocity. Then you have a velocity change, and remember that acceleration is change in velocity per unit time. And you know know the relation between velocity and angular velocity: v = ωr. That should be enough information to get there...

Hope this helps!

3. Apr 11, 2014

### Emz19

That is great, thanks a million! It is much clearer to visualise now. :)

4. Apr 11, 2014

### Staff: Mentor

5. Apr 11, 2014

### Emz19

Thanks jtbell, just had a look at the link and this is also really helpful. Thanks a mill :)

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook