Question

Question) In a Hooke's Law and Pendulum experiment, what are the possible uncertainties or errors that could occur and also how would you fix them? (min 300 words)

Answer 1

(Sources of error are offered that are consistent with the experimental results.) The sources of error in this part of the experiment are due to the precision of the location measurement using the meter stick and the accuracy of the slotted masses. The meter stick was mounted vertically and behind the spring. The location was measured relative to the base of the mass hanger. Effort was made to sight the measurements directly; however, because of the location of the meter stick it was necessary to view the meter stick at a slight angle. However, this sighting was required for each measurement, and the displacement was the difference between the location and the reference. Thus, this systematic error due to parallax should be minimal. However the random error of measurement precision remains. For displacements 20 cm or more, the uncertainty of the displacement of the spring is 0.5 % or less and has little impact on the uncertainty of k; in those cases the 1% uncertainty in the slotted masses has the greatest contribution to the uncertainty of k. However, for small displacements the displacement uncertainty has the largest impact on the uncertainty in k. For example, the 1.0 g mass displaced the spring by -0.0035 ± 0.0002 m, a relative uncertainty of 6%. (You may offer a suggestion for improving the experiment, but it must focus on the most prominent error and be consistent with the sources of errors. This is not a place to “trash” the experiment.) Using a motion sensor to measure distance would increase the precision for small displacements.