Experiment will be repeated five times, recording times of fall for each set of masses.
(B)
Increasing mass difference (keep total mass the same): Move masses from one side to
the other and repeat measurement five times, recording times of fall for each set of masses.
Data Collected:
Analysis:
In the first experiment set, it became apparent that as the mass was increased on both
sides with the same mass difference, it took the heavier side longer to touch the ground, and
the acceleration is increasing.
The denominator is increasing and the
numerator is constant therefore acceleration is increasing. If acceleration is increasing the
measured fall time must decrease from the equation, a^= 2y/t2.
In the second experiment, we found that an increasing difference between the weights
shortened the time considerably.
In both experiments the %o error calculations range from
about Lo/o to 20010, with the highest %o errors for the smallest values of acceleration. The
absolute difference between each set of values a. and am is fairly consistent
Conclusion:
By using Atwood's machine, Newton's law was successfully tested. With this experiment,
the measurement of acceleration of the masses was determined from the mass loads, and a
value for the acceleration of gravity was calculated from time measurements. The results are in
close agreement with the hypothesis that the acceleration of the object observed being directly

proportional to the net force acting on the object and inversely proportional to the total mass of
the object. Though the data recorded was not completely accurate with the calculations
conducted with Newton's 2nd Law of Motion, the approximate values were within one standard
deviation. Frictional force in the Atwood's machine and observer's reaction time are the 2 main
sources of error. One improvement is to raise the apparatus so that the distance of fall is larger
and the measured fall time is increased. Reaction time errors (essentially constant) will be
reduced as a percentage of the time measurements.

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