1. In your own words, describe the situation to be studied and each ofthe two methods used to study it.
2. List and define each of the parameters to be measured directly.
3. List any quantities that will be calculated.
4. List any diagrams that will be created during the analysis of thisexperiment.
1. In step one, you will need to hold the mass in place over the pointer. Before the rotation begins, spring will pull the mass too close to the shaft toremain over the pointer. When the rotation of the system begins, the mass willmove outward away from the shaft. It will be up to you to control the speed ofthe rotation so that the mass will remain in a circular path over the pointer.
2. Also, remember that the crossbar is moveable. If the string isnot vertical and/or the spring is not horizontal when the mass tip is helddirectly over the pointer, move the support bar until everything is properly aligned. Proper alignment is important to make sure that the centripetal forceis produced only by the spring.
3. You will have plenty of time to take the measurements for thisexperiment. Therefore, take enough time to practice rotating the mass until youcan keep the tip of the mass consistently over the pointer while the mass ismoving.
4. While measuring the time intervals, have one lab partner (the one whopracticed) rotate the mass while the other lab partner runs the timer.
1. Your results section should include both values for the force exerted bythe spring and the percent difference between them.
2. Discuss the results of step #3. Explain why using a greater number ofrotations leads to more consistent value for the the average time. Arethere limits to this, i.e. if 20 rotations give a better time value than 5rotations, is it also true that 40 rotations would give a better value than 20rotations? Why or why not?
3. Compare the differences between the rotating system with the spring andthe rotating system without the spring. Use force diagrams to illustrate yourexplaination.
4. Compare the average force value obtained from the rotating system to thatobtained using the hanging masses. Identify three factors inherent in thesystems themselves that could cause noticable differences between these two values.
5. Challenge: Using free body diagrams, explain thoroughly why the springmust be horizontal and the string must be vertical in order to obtain accuratevalues for the centripetal force in Procedure 3 of this experiment.
| Section | Points |
|---|---|
| Purpose | 1 |
| Results | 4 |
| Calculations | 4 |
| Analysis | 9 |
| Challenge | 2 |