Mass vs. Force

Purpose: The purpose of this lab was to discover the most accurate relationship between mass and force; in other words, how many Newtons (N) does it take to support a certain amount of kilograms (kg). By finding this relationship, we were able to discern and graph the best fit line.

How?:To start off the experiment, we were given various brass masses and a force probe. By keeping my arm at a constant steady height, my group hung a brass mass from the force probe. We were able to make a data table by recording the brass mass in grams and kilograms (1 g = 0.001 kg), and by recording the amount of force, in Newtons, needed to support the mass. We used a variety of masses and through our calculations we started noticing trends. By observing our trends we concluded that there was a direct relationship of 1- 10 between mass and force. For every one kilogram (1 kg), ten Newtons (10 N) were needed to support it.

Graph:With the trend established and our data table complete, our group was ready to graph our data. With mass in kilograms on the x-axis, and force in Newtons on the y-axis, our group was able to graph the best fit line for our data. By looking at our best fit line we determined the slope and used the equation y=mx+b. 

*m= slope. Δy over Δx, which in this case is 10

*b= y-intercept (where the line crosses the y-axis) which in this case is 0

After plugging in all our values we get the equation......y=10x therefore, F=10N/kg(m)+b

Note: The new equation is similar to y=mx+b where 10N/kg represents slope and "b" represents the y-intercept; however, F in this new equation is equal to force and "m"represents mass. 

The Real World: Below, I posted a couple videos that talk about the difference between mass and weight, two concepts that are commonly mistaken. Mass refers to the amount of matter in an object, but weight is a force. Weight is the "gravitational attraction that the object feels toward the Earth." When asked the question, why is it difficult to push a car? The most common response would be, "because it is heavy." Heaviness is used to describe weight, or a gravitational pull. But because the car is being pushed on a flat surface, the force of gravity does not oppose the motion. I feel that these two videos are relevant to our lab not only because we literally used brass "masses," but because when we hung the masses to the force probe, the amount of forced used is equivalent to the gravity acting on the object. 

http://www.youtube.com/watch?v=_Z0X0yE8Ioc

http://www.youtube.com/watch?v=1whMAIGNq7E