I. Lab Notes
One discrepancy was noticed in the data obtained from the computer between the time
recorded for a given data point, and its corresponding time within the file for another
measurement, though all three times for one data point should be the same. For instance, the time
recorded for point number 3 of trial 1 within the position file is 0.0615 while the time recorded
for the same point of the same trial for velocity is 0.0916 and 0.1017 for acceleration. Further
investigation revealed, however, that for position and acceleration, each time was recorded
correctly, but that the point number did not necessarily correspond to its line number. Evidently,
the sensor began recording each measurement at a slightly different time, so it became necessary
to line the data points up according to time, and not line number. Furthermore, once the position
and acceleration tables were lined up correctly, the velocity table could be lined up such that
each of its time values fell directly in-between the adjacent time value and the subsequent one.
Midway through the experimentation of the lab, it was noticed that the string came up
over the pulley towards the cart, but was being dragged down again to slide along the underside
of a bar about 2cm away from the pulley itself. Because this possibly unnecessary friction had
already been part of the data, it was left as such, but the collected data may have been cleaner
should this fact have been noticed sooner.
The purpose of this lab was primarily to calculate the acceleration of gravity through
observation of a falling mass. Varying weight was attached to one end of a string that was hung
over a pulley, while the other end was fixed to a cart on a track. When the weight was allowed to
fall, the cart accelerated into a barrier and bounced back. A motion sensor and computer were
used to gather data about the cart’s varying position, velocity, and acceleration after the weight
was released and following its collision. The data was analyzed to show relationships between
the motion of the cart, the magnitude of hanging weight, and predictions made using Newton’s
The data used in this lab was collected by a computer and exported into a series of text
files. The position, velocity, and acceleration of the cart were recorded and saved to separate files
for each of 40 trials. Each of these 120 text files contained around 120 data points, which each
included one value for time elapsed in seconds in addition to one for the measure being recorded.
This totals to approximately 28,800 recorded values in text form, which proves analyzing the
experiment as a whole using a program like excel highly inefficient.
However, the use of a programming language proved effective in executing the large