Factors that Affect the Period of a Pendulum
Objectives: Experimentally determine how the period of a pendulum is affected by
a) The mass of the pendulum bob
b) The length of the pendulum
c) The initial angle at which the pendulum is released.
To be written up in your comp. book:
Preliminary questions:
1. Define “cycle” “amplitude” “frequency” and “period” as they are used in simple harmonic motion. If you are not certain, you may find definitions in the text
2. If one were to double the mass of a pendulum bob, make a predictive statement of how you believe the period of the pendulum would be affected, if at all, and explain why you believe it will be affected in that way.
3. If one were to double the length of a pendulum, make a predictive statement of how you believe the period of the pendulum would be affected, if at all, and explain why you believe it will be affected in that way.
4. If one were to double the amplitude of a pendulum (release a pendulum bob at two times the initial angle) make a predictive statement of how you believe the period of the pendulum would be affected, if at all, and explain why you believe it will be affected in that way.
5. Suppose that a person attempting to time the period of a pendulum has a 0.10 second reaction time…that is it takes 0.10 seconds for them to see a pendulum at its highest point and to get a signal to their finger to stop the watch. Would they get a more accurate “period” if they were to try to time one cycle, or if they timed a number of cycles “x”, and then divided their elapsed time by “x”? Explain your answer with an example.
Experimental design:
Write three brief statements, one for each of the three variables to be tested, explaining what variables you will be controlling, which variables you will be manipulating (the independent variable) and which variable you will be measuring (the dependent variable).
Create three separate data tables, one for each of the three variables to be tested, in which you should record the controlled, manipulated, and responding variables. Your data table should show that you used a minimum of three different values for each manipulated variable, and that each trial was repeated at least three times.
Using a computer graphing program create three graphs, one for each of the three variables tested, showing the independent variable on the x-axis and the dependent variable on the y axis and the data points clearly labeled. A line of “best fit” should be drawn in and the equation and r-squared value of the best fit line should be given. Attach the graphs in your comp. books.
Conclusions:
Write three brief statements, one for each of the three variables tested, stating what affect, if any, the DATA shows each tested variable had on the period of the pendulum. If the data suggest a relationship different from the one you predicted, suggest a possible explanation. For each of the three variables make a statement of confidence in your results and defend.