# Rod on frictionless surface

1. Oct 24, 2013

### nil1996

A rod initially held vertically is falling on a frictionless surface when given a slight push.I just want to how the rod would move.I am thinking that the rod as a whole will move forward and also rotate about the point on the ground.

Why the rod is moving forward?(if you ask me)
I think that the CM is going in circular motion and thus will experience an outward pull. This force will take the rod forward.

But i have heard that the rod purely rotates and does not move forward as a whole.
check this link http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=2541
What is wrong in my argument?

Last edited: Oct 24, 2013
2. Oct 24, 2013

### Legaldose

I'm having trouble visualizing what you are saying. Could you be a little more explicit? Then I, as well as others, would be able to help you.

3. Oct 24, 2013

### nil1996

here is a picture
http://img191.imageshack.us/img191/3926/lyj9.png [Broken]

I want to know if the rod will rotate purely or have a translational velocity with rotation?

Last edited by a moderator: May 6, 2017
4. Oct 24, 2013

### Tanya Sharma

If the surface is frictionless ,as in the picture,the lower end slips on the surface towards right ,in a manner such that the CM of the rod moves vertically downwards .You can consider the motion of the rod as a combination of translation of CM + Rotation around the CM.

I have made a rough sketch .The red dot shows the CM.

#### Attached Files:

• ###### stick.PNG
File size:
1.1 KB
Views:
182
5. Oct 24, 2013

### nil1996

For the end to slip should there be any net force acting on it?

6. Oct 24, 2013

### nil1996

I got it
thanks a lot

Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook