Lab 2, Acceleration of Gravity, 
Courtesy of Chiung-Yuan Lin and Benli Young
Introduction

On page 15, y=(1/2)gt2 where y is the falling distance measured from the highest (or rest) point, and t is the time starting from the instant that the ball is released.

When we make a table of falling times, we will use d instead of y to represent the falling distance. However, they two are exactly the same.

Procedure

Step A

Complete the given tables in the outline.
Step B

Measure the distance d from the bottom of the ball to the receptor plate.

Step D

Do not press <enter until you finish a series of measurement with the same falling distance. Or your measured time will be erased from your computer.

After finishing a series of falling times, a data table will be shown on you screen. The Row of "Mean" stands for tawg on page 17. And we do not need to record any error at this stage.

Step F

It is not necessary to print the data table out during Lab 2. It is enough to fill your data in the given data table.



Outline for "Acceleration of Gravity", 10/11/1999
  1. Experiment title/ date
  2. Your Name, Your E-mail Address (if applicable), Your Partner, and Section No.
  3. Concept
  1. State of purpose or theory regarding this experiment you like to write down
  2. Basic formulas used
  1. Measurements and Analysis


    2. 1. Measurements of necessary constants

    Object
    Weight, Unit : (　)
    Diameter, Unit: (　)
    Small ball
    		 　 　
    Big ball
    		 　 　

    2. Measurements of gravity, g, for the small ball, referring to Page 17:

    Measured d, (m )
    Five elapsed time (sec)
    taverage (sec)
    t1
    t2
    t3
    t4
    t5
    　 　 　 　 　 　 　
    　 　 　 　 　 　 　
    　 　 　 　 　 　 　
    　 　 　 　 　 　 　
    　 　 　 　 　 　 　

    3. Results of Analysis, for the small ball:

    Plot "d versus t" graph on screen. Modify "t" to get Graph "d versus t2."

    Print out the modified graph with "statistics" for modified data and find out "g".

    Calculate %error:
    g true = 9.795 m/s2 , sg= standard deviation of slope

    [(g measured - g true) / g true] ´< 100%=

    (2sg / g measured ) ´< 100%=

    4. Do "2" and "3" again for the big ball.

  2. Conclusions

    3. Question 2: Is the acceleration of gravity the same for each ball? Is it the same for all objects?

    Requirement: You must answer this question with %error.

    Question 4: Does the straight-line fit go through the origin or is there a non-negligible y-intercept? Discuss the possible origins of any y-intercept.

    Requirement: (0.5 Point) Tell me the theoretical value of y-intercept if no error existed. Then, (0.5 point) tell me one possible sources of the systematic error which could cause a non-negligible y-intercept with a logical reason and a numerical estimation. A simple answer like "Human Error" or "Stupidity" is totally unaccpetable!

    -----------Detach it, please-----------

  3. Suggestion
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