pendulum swings or bobbing masses

We used a turn (or position) sensor connected to the computer and recorded the swings of a pendulum made of a metal rod and a weight. We tried again this time connecting the sensor to a weight on a spring.

Our results

This graph compares the oscillations of a weight swinging on a metal rod with a weight bobbing up and down on a spring.

You will find some of the questions easier if you put these results into your data logging software. Click here to get the results. (Look for other files labelled pend*).  

Looking at the results

• Describe and compare the shapes of the two graphs.
• What does this tell you about the nature of the oscillations?
• How do the amplitude and the frequency of the oscillations vary with time? Why is this?
• How might this information be useful in designing a clock?
• What do you notice about the shape of the “envelope” of the oscillations in each case?
• How might this information be useful in designing a car suspension system?

What you can do

Try for yourself: see how the oscillations change when you damp the motion of the mass and spring using a vane, a beaker of water and a beaker of oil.