My partner, Jennifer Straka, and I explored the relationships between force, mass, and acceleration in this lab about pulleys. The Lego Mindstorm car pulled in a string that went through a pulley and had a weight on the end of it, and when it finished moving, was able to measure a variety of factors within that action, including acceleration, battery discharge, and the speed at which the rope was pulled in. We were specifically paying attention to the power level of the motor, which was our force; the mass of our weight; and the acceleration.
In the first trial, we deliberately increased the mass and kept the force constant, expecting the acceleration to change accordingly. We did five different runs with five different masses. Luckily for us, our data was accurate enough that we could plot a trendline that confirmed our ideas about acceleration and mass being proportional.
As we know, F=ma. Because force was constant, when we increased mass, acceleration decreased. The relationship between mass and acceleration is inversely proportional, which this graph shows to be true.
In the second half of our experiment, we kept a constant mass and incrementally increased the force over five different levels. Again keeping in mind that F=ma, we expected that if mass stays the same, increasing force will also increase the acceleration. We were happy to discover that our findings did confirm this as true, as evidenced by the proportional trendline in our data.
Being told that force is the product of mass and acceleration is one thing, but to actually discover and prove that for ourselves is another thing completely. It’s much easier to see the evidence and understand it than to memorize a formula and assume it as true. This lab allowed us to comprehend exactly how force, mass, and acceleration relate to one another in a hands-on way.