Newton's Second Law
The objective of this lab is to study the legitimacy of Newton's Second Law by observing the relationship between force,
mass and acceleration.
, we performed five separate experiments, each with a cart on a level track. The cart is attached to a
string that is guided over a pulley and attached to a vertically hanging mass, and is accelerated when the mass is allowed
to free-fall to the ground. For the first three experiments, we simply used different masses for the free-falling mass. For
the last two, we used the same free-fall mass and added mass to the car.
The data we collected from the experiments include the masses used, and the displacement of the car as it moved along
the track. The displacement was measured by a tape-timer set at 0.1 Hz. This data was then used to calculate the
experimental acceleration vs. the theoretical acceleration.
Experimental errors are given per experiment, listed within
the corresponding data tables below.
Our results coincide very well with Newton's second law, with the exception of sets #1 and #2 (their %errors are very
large). This is probably due to human error in either the execution of the experiment or the recording of the data, or due
to friction. Sets #3, #4, and #5, however, quite agree with
. This can be seen by their percent errors (6.0%,
8.3%, and 5.6%, respectively). These %errors are likely due to our non-inclusion of friction into our calculations. Further,
as is expected, as more mass is added to the system, and the applied force is kept constant, the magnitude of
acceleration decreases. This can be seen in a quick comparison between sets #3, #4, and #5:
I think there is little practical improvement to be made to this experiment, as it serves well to give a better
understanding of Newton's second law (without terribly expensive/accurate equipment). If some improvement could be
made, it would be to allow a little more time so that perhaps 2 runs for each set of masses can be performed.