1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Lab Report Help

  1. Oct 24, 2004 #1
    I was assigned to do a Lab report on an experiment we did in class.. this is for advanced physics honors..

    I want to know if there's anything I should have that I don't .. or if something doesn't sound right?? Also .. could someone help with writing the Abstract??




    The purpose and objective of this lab is to obtain g, acceleration due to gravity, by using an inclined plane, and other materials, and to calculate g using the results. Galileo did this same experiment around four hundred years ago, only with none of the technology of today’s time and a ball instead of a blue car. Theory states that acceleration due to gravity is 9.81 m/s². This experiment tried to attain that same result using the equation g=a/sin2.
    This experiment will continue to be studied, as its results are as important as any. Galileo found the results of the experiments to lead to the answer of an important question of his time. Is Earth the center of the solar system, and is it stationary? The answer of course was that Earth is not the center of the universe, the sun is, and that it is not stationary, but constantly rotating and gyrating around the sun.

    Methods and Materials:

    A list of materials used in the experiment is as follows:

    Motion Sensor – used to measure the acceleration of the Pasco car
    Computer – used for the software
    DataStudio Software – used to show the graphs and do some of the measuring
    Dynamics Carts Track from Pasco- used for the car to go down
    Pasco Car- used to wheel down the track
    Meter Stick- used to measure how far to prop up the track
    Ring Stand- used to prop up the track
    Friction Pad- used to keep the track from sliding
    Power Links- used to plug all components together

    The procedure to this experiment with the list of materials like the one above, can be found in DataStudio Essentials; Acceleration Due to Gravity, by Pasco Scientific.


    All equipment was first hooked together and set up so that the experiment could be done. The bottom of the inclined plane was first set at 10 cm from the top of the table. The car was placed on the track at a distance of 40 cm from the motion detector located at the top of the inclined plane, and released at the same time that the DataStudio began recording. Once the car got to the bottom of the track the software was stopped. The graph of the data was then saved and four more runs were completed at 10 cm in the same way before the bottom of the inclined plane was set at 8 cm, then 6 cm, then 4 cm, and finally 2 cm. Five runs were also done in each of the other settings. Once the data was collected, the measurements and calculations were done. We first found the average acceleration of the five runs for each of the settings and then found the angle of the inclined plane at each. Lastly the acceleration due to gravity was found. The equations and findings are located in the appendices.


    The results of the experiment were not the ones expected. Diagram 1 shows how the results were obtained. In the diagram g is equal to acceleration due to gravity, and a is equal to the acceleration of the car down the inclined plane. Theta is equal to the angle between g and the y-axis. To find g the formula g=a/sin2 or a=g (sin2) can be used. For example, the average acceleration of the five runs tested for an angle of 2.5° was .3968 m/s², so when dividing .3968 m/s² by sin 2.5º an answer of 9.1m/s² is found. The actual acceleration for the measurement of 2.5º should be .427 m/s², which shows some kind of error in the experiment. The possibilities of error are located in the discussion. The tables and graphs for the five runs of the 10cm measurement are attached at the end of the lab report. The calculation for each run and measurement is located in the appendices.

    Discussion: (I have not gotten to this yet @_@)





    The accepted value of acceleration due to gravity is 9.81m/s². None of the calculations for this experiment came out to that exact result. The closest calculation obtained was 9.6 m/s². Acceleration due to gravity is in fact 9.81m/s² but there were a few possible errors in our experiment.
  2. jcsd
  3. Oct 24, 2004 #2
    Diagram 1 isn't showing.. but I don't feel like hosting it .. its just a quick diagram of the inclined plane and where theta is compared to acceleration and g
  4. Oct 24, 2004 #3

    Tom Mattson

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Actually, once you finish the rest of the report, you'll have practically already written it. It will just be scattered throughout the report.

    The Abstract is an overview of the experiment. It tells the reader what happened before he gets to the meat of the report. It's the first thing the reader sees, but it's the last thing you should write.

    In a few sentences, state the objective and the method(s) used to accomplish the objective. You should also state the main numerical results, together with their uncertainties. In this case, your numerical result is the acceleration due to gravity. You'll compute the uncertainty with respect to the so-called "accepted value".
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook