Lab 3 - Acceleration of Gravity on an Inclined Plane

Objective: To find the acceleration of gravity by studying the motion of a cart on an incline, while gaining more experience with the tools that will be used during lab.

Procedure: Using the motion detector, aluminum track, and cart we tested the acceleration of gravity.  The steps were pretty simple in this process.  First we leveled the track, with one end elevated.  The motion detector was located at that elevated end to track the cart.  Measurements were taken to calculate the angle of the track, which would be needed later to calculate the gravity.  A few test runs were done to make sure that the motion detector was working, and to give us an idea of how hard to push the cart.  As the cart traveled up the track it would slow to a stop and come back to the bottom of the track.  The motion detector would capture the movement of the cart and the computer would graph it.

Data: For the first set of test runs, block of wood was turned on its side to elevate one side of the track.  The measurements were taken to determine the angle of the track:

 Using the calculator, sin theta = 9.55/228 = 2.40 degrees.

The motion graph for the first set of tests we all similar to this one:

Motion graph at 2.40 degrees

Once these were understood, the testing could begin.  For this height, 3 tests were completed.  The graphs from these tests are shown below:

Test 1

Test 2

Test 3

Once these were completed and everyone felt comfortable with the results, The track was raised and 3 more tests were performed.  Here are the corresponding graphs:

Using the calculator, sin theta = 18.65/228 = 4.69 degrees.

Motion Diagram at 4.69 degrees

Test 4

Test 5

Test 6

Possible sources of error: This lab seemed to be stricken with error.  The first go around one of the linear fits was not completed, and this was not noticed until after the equipment was put away.  This was partially due to the fact that most of the team members were not reading the documentation on how the lab was to be done.  As a result, after half of the team had left, the second half stayed to completely redo the lab.  Most of the team just had to take his word that he did the lab correctly.

Common sources of error are the measurements.  We have measured the best we can with the yardstick that was provided, and the motion detector gets distracted easily and picks up various other movements.  This was the cause for several runs to be completed a second and third time to be able to get data that we could work with, and was closer to the expectations.
 

Questions: For each run, we were expected to calculate the force of gravity using the formula that was provided in the write up.  For each test run, the calculations are illustrated below.

Conclusions: