Prior to our second experiment with a robotics lab, my class learned about force and motion relating to Isaac Newton’s fundamental laws of physics. Of the three that we discussed, his second law applies most accurately to our experiment from February 6th, which is that an object’s force is equal to its mass multiplied by its acceleration (F = ma). According to the information provided to us, as an object increases in mass, its acceleration will decrease with a fixed force; in other sense, if an object has a fixed mass and increases its power level, its acceleration will also increase. This is the ideal preview for our robotics experiment in which we had to use a motorized pulley to record its variants by experimenting four times with the same mass and four times with the same power level.
My group was given a pendulum-like weight to suspend from a provided structure, creating a pulley system with the computerized motor at the base. The gold object meant to hang from the structure could be taken apart to decrease its mass. The instructions were to allow the motor to run for approximately one second (although this proved difficult to calculate manually) and measure the stopping height of the object with a ruler.
For the first set of trials, we sustained the object’s mass at 0.23 kilograms and varied the power level inputted into the LabView program. The results of this trial group can be seen in the first 4 columns in this Microsoft Excel chart:
Based on the outcomes of these four trial experiments, we were able to come to the conclusion that the object experiences a higher rate of acceleration as the power level, or force, is increased. In the second set of trials (as shown in the lower four columns of Figure 1), we sustained the power level at 75% and only reduced the mass of the object. Compared to the data from the previous trial set, the greater force resulted in increased acceleration, which stayed fairly constant throughout the four experiments.
Unfortunately for my group, an unsure amount of our data was skewed in the LabView program, leaving us with shaky results to use for the final calculations, which had to be added to our experiments. The two new variables were the object’s different values of potential energy and the overall power used by the computerized motor. Referring to the chart Figure 1, the object’s potential energy is identified in the column labeled mgh, referring to the mass multiplied by the measured height and the constant rate of gravity (which, as we know, is 9.8 m/s squared). The power used by the motor falls under the column labeled mgh/t, which uses the same values divided by the allotted time. As evidenced by Figure 2, the comparison of the power level and the power used by the motor stays with a fairly constant curve, only slightly varying in the portion of the experiment concerning the single 75% power level. Despite our technological issues, I would have to say that the steady increase in power usage relating to the programmed level is what we expected to see by the end of our lab activity.
