This lab requires the use of the Phet simulation: Lady Bug Revolution. The simulation can be accessed at:
Part 1: Intro
- Select the tab labeled: “Intro”
- Select “show velocity vector” and “show acceleration vector” on the bottom left.
- Select approximately 190 degrees/second for the angular velocity. Record your exact value here: ____________.
- Measure the distance of the ladybug from the center using the ruler and record the value in the table below. Then click the “step” button 5 times to advance the simulation. Record the angle. Using q = s/r, calculate the distance the ladybug has traveled along the path and record it in the table. Reset the simulation.
- Repeat step 4, each time placing the ladybug at a different location on the wheel. Vary the number of “steps” used each time as well. Record all data in the table below.
| Angle | Measured distance from center | Distance traveled along the circular path (calculated) | Velocity (calculated) | Moment of Inertia (calculated) | Angular acceleration (calculated) | Moment of Inertia | Torque |
- Calculate the velocity of the ladybug at each position using the equation v = w r and record in the table.
- Recall from Chapter 5 that the centripetal acceleration in uniform circular motion is given by a = v2/r. Using this and the relation between linear and angular acceleration: a = a r, calculate the angular acceleration and record it in the table.
- At each position, calculate the moment of inertia (I = m r2), assuming a mass of 2 grams for the ladybug.
- Calculate the torque acting on the ladybug at each position and record in the table.
- Summary: write a one paragraph summary describing what you have learned about rotational motion from doing this lab. Your summary should include an explanation of each of the measured/calculated quantities.
