# Acceleration directions and friction.

1. Mar 2, 2013

### SaxonMilton

Ok, I am analysing the situation in the attached image, and I am trying to find the frictional force between the nylon string and the top of the piping, but I am not sure what the value of acceleration will be. I understand how to do this when there is only acceleration due to gravity, but with this, centripetal acceleration is involved. Do I need to use vector resolution and find the total acceleration?

#### Attached Files:

• ###### centripetal force appartus.PNG
File size:
6.8 KB
Views:
86
Last edited: Mar 2, 2013
2. Mar 2, 2013

### alex2344

Ok, its very easy. Use total acceleration

3. Mar 2, 2013

### lep11

What are the forces acting on the system?

4. Mar 2, 2013

### SaxonMilton

Only gravity, and then also centripetal force once the rubber stopper begins spinning. But there is also the friction between the string and the pipe

5. Mar 2, 2013

### PeterO

Compared to the other forces involved, that friction is negligible.

6. Mar 2, 2013

### SaxonMilton

Yes, we also thought so, but we ran an experiment, and we found after comparing our results to what the values really should be using v = √(Fr/m), our values seemed to increase more so than the true values, so we believe that the additional frictional force is contributing and increasing the speed.

7. Mar 2, 2013

### PeterO

Was your piping a glass tube with the ends rounded by heating?

How were you measuring V. Why not start with 4∏2rm / T2 rather than mv2/r - as it is easier to measure the Period.

8. Mar 2, 2013

### haruspex

Pls explain more about the experimental procedure, what was measured, and the results.