SPH 3U1 Updated: Nov 2008
Lab 1A – uniform motion experiment
The purpose of this lab is to familiarize the student with the use of ticker tape timers as well as graphing and analyzing data.
Part I. Ticker Tape Instructions:
à You will attempt to pull the tape at a constant velocity.
· use about 2 m of tape (two arms lengths), perhaps a bit less
· the timer makes 60 dots per second (60 Hz = AC electrical frequency)
· draw a line through every 6 dots (so that there are 6 intervals between dots) - this distance corresponds to 0.1 second.
· for distance, measure distance from the end of the tape to each line.
· displacement is the distance between each line.
· speed is displacement over time
· you can work with one partner – using the same ticker tape, but each of you must hand in the data table, graphs, and answers to questions.
· you should probably keep your ticker tape until you have done your graph, (in case there is some problem with your graph/data – then I'd like to look at your ticker tape)
· make sure that you hand in your data table.
Analysis:
1. Plot a distance-time graph. (It should always be increasing)
2. Was your motion uniform? (i.e. constant speed, i.e. zero acceleration) How can you tell?
3. Using a line of best fit, determine your average speed from the d-t graph.
4. How would the d-t graph change if you moved slower?
5. Plot a speed-time (v-t) graph
6. Draw a horizontal line of best fit
7. Write down your average speed from the v-t graph (read it off of the speed axis)
8. Are your two average speeds (from #3 and #7) similar?
Note: you don’t have to use all of the points. You may be able to reasonably ignore the first few (if it started jerkily) or the last few (if you stumbled).
Part II. Computer Instructions.
9. Now use the computer system to collect and analyse data (trying to move at a constant velocity).
10. Get a d-t graph and a v-t graph.
11. Find the average speed from each of them
12. Compare these two speeds.
You may need to work in groups of 3. The graphs from the computer can be photocopied, but each person must hand in his own analysis and questions.
Final Questions:
13. Discuss any errors (if there were any - hopefully you fixed them). (#13, #14 relate mostly to part I)
14. Also comment on how accurate you think your results are. (e.g. The tape was pulled at 0.33 ± 0.02 m/s)
15. What things did you learn from each way of doing the experiment (ticker tape vs. computer)?
16. Which way is better for learning physics? Support your answer with an explanation (unless you can’t tell).