PASCO ME-6950 PAScar with Mass - Manual (Page 9)

012-07361B PAScar with Mass
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NOTE: The car’s acceleration falls to zero when the falling mass hits the floor.
5. Hang enough paper clips onto the dangling loop in the string until the car will just
continue to move without apparent acceleration when barely nudged. This small added
mass will compensate for friction in the system and will be ignored in the following
calculations. The paper clips will remain attached to the loop throughout the experi-
ment!
6. Move a 10 gram mass from the bed of the car to the hanging loop and pull the car back
to a clearly marked starting point. Determine the distance d that the car will move from
the starting point to the bumper block and record this distance at the top of Table 3.1.
NOTE: The total mass of the system will remain constant throughout the experiment.
7. Practice releasing the car being careful not to give it any push or pull as you do so. The
best way to do this is to press your finger into the table in front of the car thereby
blocking its movement. Quickly pull your finger away in the direction that the car wants
to move. At the instant you pull your finger away, start your stopwatch. Stop your
stopwatch at the instant the car arrives at the bumper. To eliminate reaction time errors,
it is best that the person who releases the car also does the timing!
8. Determine the average time for the car to move through the distance d, having been
released from rest. Record the average of the four time trials in which you have the
most confidence in Table 3.1. Repeat for all of the masses given in the data table.
9. Excluding the pulley, determine the total mass of your system, M
Total
(car, added
masses, string) and record at the top of Table 3.1. (It will be close to 1100 grams, but
you might want to check it on a balance.)
10. Fill in the table using your data and the equations given in the Theory section.