Name: Dr. Julie J. Nazareth Lab Partner(s): Physics 122L/132L Date lab performed: Section: Simple Harmonic Motion Spring-Mass System Table 1: Measurements for a Coil Spring in Static Equilibrium Added Mass, Distance above floor, Elongation***, Weight+++, M (kg) d ( ) x ( ) W ( ) 0 0.00 ----- 0.100 0.200 0.300 0.400 0.500 *** elongation, x = d(M=0) – d(M) +++ weight, W=Mg

Table 2: Measurements for an Oscillating Coil Spring

Mass of spring, ms (kg) Total time for 30 Period (time for Suspended Mass, oscillations, one oscillation), Period Squared, m (kg) t (s) T (s) T2 (s2) 0.100 0.200 0.300 0.400 0.500 Optional: 0.00

Plots: On separate sheets of graph paper, show the following plots. Draw a best fit line to your data. If you don’t know how, ask the instructor. Calculate the slope of the best fit line using two easy to read points on the line that are not data points. Draw small boxes or circles around the points chosen to calculate the slope. Remember to title and label your graph appropriately.  Plot Mg vs. x (Suspended weight vs. elongation). Determine the spring constant, k, from the slope of the plot.  Plot T2 vs. m (Period squared vs. suspended mass). Draw your graph so that you can measure the x-intercept (what the x-value equals at y = T2 = 0) directly from the plot. Use x-axis limits of -0.100 kg to +0.600 kg. Determine the spring constant, k, from the slope of the plot.

Table 3: Results from the Spring-Mass System Slope Spring x-intercept Mass of Plot Constant, measured off oscillating part Value Units k ( ) graph of spring, Mg vs. x ( ) mo( )

Lab: Simple Harmonic Motion Updated 09/23/09 Data and reporting score: T2 vs. m Calculations: Show the following calculations. Include units in your calculations. Ignore formal significant digit rules (but be reasonable).  Sample calculation of the weight, Mg, of the added mass used in steps 1-4

 Slope of Mg vs. x

 Sample calculation of the average period of oscillation from the total time, T (steps 5)

 Slope of T2 vs. m

 Spring constant, k, from the slope of T2 vs. m

Question 1: Calculate the fraction of the total mass of the spring that is oscillating. m o  ms

How does your estimate of mo (the mass of the part of the spring that is oscillating) compare to one third (=.33) the mass of the spring? If your value is not close to one third, why do you think that is?

Don’t forget to write your summary! (As usual, start your paragraph with an introductory sentence telling your audience why you did this lab (the purpose or objective). Some things to think about and discuss in your summary…Look at your part A graph: Does the spring obey Hooke’s law? If not, ask your instructor right away! How well do your values for the spring constant (parts A & B) compare with each other? If they are not reasonably close, what things beyond your control might have affected your experiment? (Make sure that you define what you consider to be “reasonably close”: a percent difference of 1%, 5%, 10%, 20%, etc.; the same

Lab: Simple Harmonic Motion Updated 09/23/09 order of magnitude; the same within formal uncertainty; etc.) Talk to your instructor right away if your results are far off from each other!)

Lab: Simple Harmonic Motion Updated 09/23/09