By rearranging this expression it s possible to derive the 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 . 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. Mm this gives a relative uncertainty of 0. Mm and an estimated absolute uncertainty of 0. Mm due to human error measuring from the end of the string to the center of the mass attached. This leaves us with an overall uncertainty of 0. Mm.
The second measurement is time this is measured using a stopwatch. The percent discrepancy error is 31. 59%. Sources of error include. Guessing the center of mass for the bob introduced systematic error. Measuring to a different point on the metal ball could have introduced random error.
Releasing the pendulum from a different angle each time would introduce random error. An oval track of the pendulum would introduce systematic error. Bouncing or vibrating would also introduce random error. The length of the string constantly changing introduces systematic error.