10/05/2016 : Conservation of Energy - Mass Spring System

Lab #12: Conservation of Energy - Mass Spring System

Name:    Charles Xu,

Partner:  Anthony, Michell

Date:      10/05/2016

Statement:

In this experiment, we set up the vertically-oscillating mass-spring system, and using logger pro, motion sensor, and force sensor to collect datas. Then we compare Kinetic Energy, Gravitational Potential Energy, Elastic Potential Energy, and Total Energy.

Summary:

For this experiment, we set up out mass-spring system with the spring we used for lab #11, so that we are able to have the spring constant. Instead of using 250 grams hanging mass, we used 1 kg hanging mass. We stretch the spring and then release it with the motion sensor collecting datas. Then, using logger pro we plot position vs. time and velocity vs. time graphs. 

Setup of Mass-Spring System

Position vs. Time graph and Velocity vs. Time graph

As the result, we got two sin waves as the graphs. Later on, we added four more calculate columns, which are Kinetic Energy column, Gravitational Potential Energy column, Elastic Potential Energy column, and Total Energy column. Then we plot KE vs. position graph, KE vs. velocity graph, GPE vs. position graph, GPE vs. velocity graph, EPE vs. position graph, and EPE vs. velocity graph using logger pro.

KE vs. position graph, KE vs. velocity graph

GPE vs. position graph, GPE vs. velocity graph

EPE vs. position graph, EPE vs. velocity graph

and last step, we plot KE, GPE, EPE, Esum vs. position graph and KE, GPE, EPE, Esum vs. time graph.

KE, GPE, EPE, Esum vs. position graph and KE, GPE, EPE, Esum vs. time graph.

Conclusion:

By the conservation of energy, the total energy should stay as constant. However, in this experiment, we have the total energy as decreasing function. To explain the error, I think the elastic potential energy and gravitational potential energy not only convert into Kinetic energy but also some work done by the air resistance. This is one of the reason why the sum of energy is decreasing.