Energy of a bouncing spring

Analysing the energy of a bouncing spring is a common exam question. In this task you will use tracker to analysis the motion and use the data you gather to examine the energy transformations than occur.

Consider the 2017 exam questions..

The first thing we need to determine experimentally is the spring constant for the spring. This is found from the gradient of the force - extension graph. Use the excel spread sheet below and determine the spring constant for your spring.

Once you have a spring constant you are going to use your spring to examine the oscillation of a mass. Choose a mass size that enables the spring to oscillate freely. Take a video, making sure the ruler and is clear in your video. and import it into Tracker.

Set up the tracker so that the lowest point of the oscillation is at zero. Track using a point mass over at least three oscillations. Choose a point that does not get too blurred with the motion. I chose the hook

Set up the oscillation graph by making sure you are looking at the variation in y vs time (default is x).

Step through the frames and examine where on the graph the each step appears. Answer the following questions.

1. What is the shape produced by the y displacement graph?

2. What is the gradient at the top and bottom the masses motion?

3. What does this signify?

4. Where is the mass travelling the fastest?

5. How is this illustrated in the graph?

6. Determine the maximum speed for your second oscillation when the mass is falling

8. Using the data from your second oscillation calculate:

9. Is there energy loss of the three oscillations? Justify your answer?

10. Draw a graph of the three energies on the same axis, against displacement in the y.