Lab Report
Experiment # 5
Pendulum and the Calculation of g
David Case:
February 14, 2015
Experiment #5
Pendulum and the Calculation of g
Objectives:
To calculate the acceleration due to gravity by observing the motion of a pendulum. To investigate the effect of varying mass on the period of a pendulum. To investigate the effect of varying the length of a pendulum on the period
Materials:
stopwatch support for the pendulum tape set of washers protractor spring scale tape measure weight bag Lab Notes: 1. Changing the amplitude:
A. Length: 1. Attach a small plastic bag to the spring scale.
2. Add washers to the plastic bag until the scale measures approximately 25 g total. The filled bag will hereafter be referred to as the bob. Record this value as “Mass of bob” in the place provided in Data Table 1.
Table 1: Trial of values at varying degrees
Length of string: 100cm= 1 m Mass of bob: 25g= 0.025kg
Placement of Bob Degrees
Amplitude (bob horizontal displacement) cm
Trial 1 (s) 5 cycles
Trial 2 (s) 5 cycles
Trial 3 (s) 5 cycles
Avg. Time (s) 5 cycles
Period 1 cycle
5°
6
10.00
10.11
10.62
10.24
2.04
10°
15
9.45
9.68
9.55
9.56
1.91
15°
23
9.54
9.69
9.86
9.69
1.96
20°
34
10.06
9.99
9.91
9.98
1.99
25°
39
9.77
9.81
9.67
9.75
1.95
30°
46
9.75
10.12
9.92
9.93
2.01
3. Measure a piece of string that is approximately 120 cm in length. Tie the string around the top of the bag so that the washers cannot fall out. Suspend the bob from this string so that it measures exactly 1 m (100 cm) between where it attaches to the support and the bottom of the bob.
4. Use tape to affix the protractor behind where the string is attached to the support so you can measure the pendulum’s amplitude in degrees. The center hole in the protractor should be located directly behind the pivot point. The string should hang