Gyroscope Investigation Lab

Get the Lab: Lab-GyroscopeInvestigation.docx

How to do the lab:

Gyroscope Investigation

1. You will need a gyroscope, a gear puller, a gyroscope stand, and a love for rotational mechanics.

2. Get the gyroscope spinning by using the gear puller. Hold the gyroscope firmly, and pull the handle - being careful not to strip the little teeth. Play with it over a table. If it drops on the floor it will break. Come up with a stupid gyroscope trick.

3. Get the gyroscope spinning anti-clockwise as seen from above (This way the L vector is pointing up), put the bottom of the gyro into stand Note carefully which way the gyroscope precesses.

4. Draw careful diagrams that a) show the direction of the torque on the gyroscope (Due to gravity) the axis about which this torque acts is the stand G = r x F, so r is away from the stand, F is straight down, b) show the direction of the angular momentum vector, c) show that the direction of precession has the tip of the L vector going in the direction of the torque.

5. Answer these questions:

A. Measure the mass of the rotor by weighing the gyroscope, and subtracting the 23.5 grams that is the cage. Measure the radius of the rotor, and use a formula like I = mr² (or is it .9mr²? – feel free to make your own formula) to find the moment of inertia of the rotor in kgm².

B. The axle has a diameter of 3.9 mm (0.0039 m). Supposing the puller was moving about 1.5 m/s at the end of your pull,

1. calculate the angular velocity of the gyro, (use v = wr) and

2. calculate the angular momentum of the gyro. (L = Iw)

C. Calculate the angular momentum of the earth (L = Iw). (use the interwebs to find the mass, radius, and period of rotation. Assume the earth is a sphere (²/₅mr²). w = 2p/T. You can also just go to wolfram alpha and type “angular velocity of the earth”) Show that it is about 7x10³³ kgm²/s (be a bit more exact)

6. Leave your gyroscope exactly the way you found it.

Here’s what you turn in:

1. The diagram as explained in part 4.

2. The answers for part 5.