Physics

Vandebilt Catholic High School

W. Dupre

 

Lab: Measuring the value of “g” with a Pendulum

 

Purpose:           To prove the Law of Free Fall, which states that ALL objects, only under the influence of gravity will                             accelerate toward the center of the earth at 9.8 m/s2.  Furthermore, the value 9.8 m/s2 is constant, regardless                         of the mass of the object.

 

Concepts:         Free Fall, Acceleration, Measuring Skills, The pendulum equation: T = 2p (L/g)1/2

                        {T = period of the pendulum, L = length of the pendulum, g = acceleration due to gravity}

 

Materials:         Stopwatch (or watch with a second hand), meter stick, protractor, pendulum

 

Procedure:

1) You are to use an amplitude of 10° for all pendulum trials.

2) The period of a pendulum is the time required to make one complete cycle of motion.

 

Data

                                                                                    Part A                          Part B

 

1) Pendulum Bob                                                          Small                            Large

2) Length of the Pendulum (m)

3) Trial 1 Time required for 50 cycles

4) Trial 2

5) Trial 3

6) Avg. Time required for 50 cycles. (s)

7) Period (T) of the pendulum. (s)

8) Percent Error (%)

 

Sample Calculations:     Include all necessary steps.

            1) Show calculation for the period of the pendulum in part A.

            2) Show the calculation of “g’ in Part A.

 

Error Analysis: Perform a complete percent error analysis using 9.80 m/s2 as the accepted value of                                ”g’.

 

Conclusions:     Write conclusions in paragraph form. Discuss the purpose of the lab. Was it achieved?                                                   Discuss the role each concept covered iii the lab played in achieving the purpose. Add your own comments.

 

Questions:

            1) Why can a pendulum be used to determine the value of “g”?

            2) Does the mass of a falling body affect the value of “g”? Use the results of your lab to justify your answer.