Help Understanding Vectors, Equilibrants, and Force Tables

[munchy35]

Homework Statement

I performed a physics lab in which we had a level force table with a string around a post in the middle with four strings attached. we then attached pulleys for the strings and weights. we used vectors and weights to find the equilibrium - when the ring was centered. It is a pretty common lab. I'm just having difficulty answering analysis questions.

1. Suppose that the weight holders in this experiment all have the same mass. May their masses be neglected? Explain.

2. If the force table were tilted at a considerable angle, would the results be altered in any way? Explain.

3. Discuss the effects of friction on the measurements.

Homework Equations

No equations!

The Attempt at a Solution

1. I don't think mass could be neglected because force is a vector quantity - they have magnitude and direction. Without the mass, there is no magnitude. ...Is that wrong? Or worded wrongly?

2. The results would be altered if the table was tilted...not sure of explanation. The levelness of the table allows results to be accurate. Adding a tilt...would cause more mass to be added to one side to level out the ring.?

3. Friction - existed in the pulleys preventing the pulleys from transferring full amount of tension to the ring

I just need help answering and wording my answers.

Also would sources of error for lab include...
-friction
-inaccurate measurements from the lab members - not precise measurements
-inability to add a fraction of a weight to a weight holder
-force table might not be completely level

Thank you!

 

[TSny]

1. I don't think mass could be neglected because force is a vector quantity - they have magnitude and direction. Without the mass, there is no magnitude. ...Is that wrong? Or worded wrongly?

I don't think the explanation is satisfactory. If you think the mass of the hangers cannot be neglected, then you might construct a specific example with numbers to prove your point.

2. The results would be altered if the table was tilted...not sure of explanation. The levelness of the table allows results to be accurate. Adding a tilt...would cause more mass to be added to one side to level out the ring.?

Would the weight of the center ring have any influence?

3. Friction - existed in the pulleys preventing the pulleys from transferring full amount of tension to the ring

OK. Can you show that friction in a pulley would imply that the tension of the string on one side of the pulley is different from the tension of the string on the other side of the pulley? Would this cause error in the results of the experiment?

Also would sources of error for lab include...
-friction
-inaccurate measurements from the lab members - not precise measurements
-inability to add a fraction of a weight to a weight holder
-force table might not be completely level

You should discuss the sources of error using complete sentences and being as specific as possible. For example, don't just write "inaccurate measurements from the lab members". Instead, briefly discuss which particular measurements were likely to have introduced the most error and explain why.