Rubber Band Cart Launcher

In this week's lab we launched a glider from a rubber band using an air track, and used a photo gate sensor to measure the velocity. We changed the distance of the rubber band being stretched for each trial. There were five trials, with the distance  from 1-5cm, or 0.1, 0.2, 0.3, 0.4, and 0.5 meters. We recorded the velocity of the cart (dependent variable) in a data table, and then repeated the experiment to get the most accurate statistics possible.

Units used:
m = meters
v = velocity
J = Jules (Energy)
K = Kinetic Energy
Us = elastic potential energy

Data:

Using the Vernier Graphical Analysis app, I created a best-fit line for all of the data we collected, using the Energy as our Y-axis, while the average of the velocity was our x-axis.

 Based on our graph, we noticed that the slope was half the mass of the cart. all of this allowed us to derive the equation for kinetic energy! KE=1/2(m)(V^2)

 In the LOL chart below, energy is transferred from elastic potential energy (rubber band) to kinetic energy (motion). When something is in motion, kinetic energy is being used. Because potential energy is transferred into kinetic energy, energy and velocity are directly proportional.

Real-World Connection: 

For example (slingshot), as the person pulls back on the slingshot, they increase the distance stretched. Therefore, there is an increase with the elastic potential energy. As the slingshot is released, the elastic potential energy is transferred into kinetic energy, which puts the ball in motion. The velocity of the ball is proportional to the kinetic energy. Therefore the more distance being pulled back on the sling, the greater the kinetic energy will be, and the faster the ball will go.