Force equals mass times acceleration; an equation important both to our experiment on Newton’s Second Law and sustainability issues in general. This experiment tested the relationship between mass, power, acceleration and potential energy; all important tools of measurement related to energy.  Mass and acceleration are inversely related according to Newton’s Second Law equation. This means that when one value increases, the other decreases.  A pulley system was set up in witch one end a motor was mounted and the other a set of weights. The motor pulled a string attached to the object causing it to rise at a specific acceleration depending on the objects mass. For the first part of the lab, we showed this by decreasing the mass of the object (the object will be considered the weights and the stand in which they are placed).  You will see based on our data that as the object became lighter the acceleration increased.  The first mass we used was 210 grams (g.) or .21 kilograms, which equated to an acceleration of 39.53 RPM/s. When the object had a mass of 90 g or .09 kg it’s acceleration was 51.24 RPM/s, proving that as mass decreased the acceleration increased. As with acceleration, speed also increased with a decrease in mass.

For the second part of this experiment acceleration of the object was tested via a change in power (force in Newton’s equation) instead of mass. 100% power left us with an acceleration of 89.32 RPM/s and when this power was dropped to 60%, the acceleration was 21.80 RPM/s.  This shows us that when one value is kept constant on the right side of the equation, force increases or decreases, depending on the increase or decrease of the value that changes.

Although not physically tested (the computer calculated this information) the relationship between the percent of power and the actual power used was linear. For each trial our power was 20% less than the previous, while each measurement of power used decreased by roughly .09  each trial.  Another calculation not physically tested was the potential energy of the object.

Potential energy was calculated to demonstrate the Law of Conservation of Energy. The potential energy of the object increased as it neared the top of the pulley system. Potential energy is measured in Joules, as is force. Theoretically, the force used to move the object to the top of the pulley system is the same as its potential energy, which is why energy is said to be conserved (did not work out when I calculated this).  Power is similar to potential energy and force, but is different because it is dependent on time (wwwphyscisclassroom.com). By definition power is joules divided by time and measured in what is called Watts (wwwphyscisclassroom.com).

When comparing the mass of the object and battery discharge, oddly enough the battery discharge stayed relatively the same regardless of the objects mass. The three recording’s of battery discharge were 42, 41, 69 and 41. So roughly in the 42 or 41 kv range. It is unknown why one of the discharges was randomly 69 kv. It would be expected that the battery discharge would decrease with the decrease in mass because theoretically less work is being done, however based on the results this did not happen (lab outline). It was posted in the outline of the lab that battery discharge is inaccurate which I’m assuming is why our data appeared the way it did. The outline also talked of the significance of battery discharge and its correlation with potential energy. Potential energy is theoretically equivalent to battery discharge. This makes sense because potential energy is the amount of energy the object has when it is at the top of the pulley system. However, in order to reach this point an equivalent amount of energy must be used, in the form of battery discharge, to move the object to that position.

As Albert Einstein discovered, mass is equivalent to energy, which is why this equation of F=ma is so important to sustainability related issues. In order to obtain energy we need something with mass, which is why we don’t get energy from nothing. This mass also needs to be put into motion, or accelerated which also takes energy (Pandora’s Promise, Stone). The movement and acceleration of particles and their mass are used to calculate energy. Energy they we are currently running out of. This is why there is an energy crisis. In this experiment we also calculated potential energy, which is important when talking about fossil fuels, because fossil fuels are in fact pure potential energy, and unfortunately fossil fuels are not unlimited.

Works Cited

Pandora’s Promise. Dir. Robert Stone. Prod. Dan Cogan, Paul Allan, Jody Allan Aimee, and Frank Batton. By Robert Stone. Perf. Gwyneth Cravens, Leonard J. “Len” Koch. 2013. DVD.

“Work, Energy, and Power – Table of Contents.” Work, Energy, and Power – Table of Contents. The Physics Classroom, n.d. Web. 14 Oct. 2013