# Translation and rotation

1. May 30, 2008

### Jason03

Heres the diagram for the problem...

http://img78.imageshack.us/img78/3248/35090397eg3.jpg

heres my work...

http://img141.imageshack.us/img141/8352/33iw6.jpg

I made my conversions.... im starting by finding the speed at D.....its not zero because of the angular velocity.....but Im trying to figure how to add the two x components...

the translational x component should be .833 ft/s......but for the rotational I need to account for omega.....

2. May 30, 2008

### Dick

What's the rotational speed? Is that the problem? It's r*omega. So that's the rotational speed. Now just split the velocity vector into xy components. This is basically an identical problem to you last post.

3. May 30, 2008

### kamerling

And what is the question?

4. May 30, 2008

### Dick

Good point. In the last post is was to compute the velocities at the various points.

5. May 31, 2008

### Jason03

The problem is asking for the velocity at points D and B...as well as if the object is slipping.....Im still trying to figure out point D first

6. May 31, 2008

### Jason03

ok I found D....it was just the rotational - translational ....

I used the V=r*omega to get the rotational

$$V_{d} = .999 - .833 = .166 ft/s = 2 in/s$$

but actually I think the signs should be reversed if you look at the vectors in my FBD...that makes sense because the magnitude is the same and the direction should be to the left which is negative...

Last edited: May 31, 2008
7. May 31, 2008

### Jason03

ok I found the velocity at point B as well.....im just not sure how to tell if the wheel is slipping or not...

8. May 31, 2008

### Dick

If the velocity at D is non-zero, then it's slipping. If it's not slipping then point D is moving at the same speed as the road and has zero velocity.

9. May 31, 2008

### Jason03

Thank You...thats what I thought....