Pendulum Jacob Lamer Group members: Josh, Courtney, Ashley Abstract: Determine the acceleration due to gravity using a pendulum. Introduction: A simple pendulum consists of a mass suspended by a length of string. When set Oscillating, the mass will have a period “T” given by the following equation. This equation shows the only variables that affect the rate at which the pendulum swings is the length “l” that is measured to the center of the object’s mass and the acceleration due to gravity “g”. By rearranging this expression it s possible to derive he following.

As seen from the expression, a plot of pendulum length verses its period squared will yield a straight line. The slope will be dependent upon the local acceleration due to gravity (9. 803 m/so) Procedure: Since the length to be used in this experiment is the distance to the center of the pendulum’s mass, the diameter of the bob is estimated and marked with an expo marker. With the string measured the pendulum is set to swinging gently back and forth. Do not allow the angular displacement of the wings to be more than 10 degrees, as this will cause deviation from the predicted period.

With a stopwatch, measure the time required for the mass to complete 25 oscillations. Record this time as well as the length of the string. Repeat the procedure for seven shorter lengths. With this data plot a graph of pendulum length (l) verses period squared (TO). Draw a line of best fit and determine its slope. From this sops, find the local acceleration due to gravity. Calculate the percent error using the accepted value 9. 803 m/so. Two measurements are made in this experiment. “L” the length of the string is measured using a meter stick which has a lowest gradation of 0. 001 m this gives a elating uncertainty of 0.