University:
Widener University
Course:
ESSC 103 | Intriduction To Earth Science
Academic year:

2023
Views:

80

Pages:

1
Author:

mercerizijyo

Geostrophic Motion — Rotating table experiment The link gives information on how the parabolic surface was created. If the table rotates at exactly the right speed (3300 on the readout), the centrifugal force will exactly balance the component of gravity along the parabola down towards the center (prove this can happen mathematically?). You can show that the equations of motion in the rotating frame are d2 x ˆ × dx = Ω2 x − Ω20 x − 2Ω k 2 dt dt The best way I’ve found to demonstrate the balance when Ω = Ω0 is to put a level ﬂat on the surface, along with a marker, and then, when the table is rotating to but the ball against the level. Then you can remove the level, leaving the ball near the marker. It should just stay there as viewed by the co-rotating camera. 1) Now slow the table down to 3000 so that the inward force is stronger than the outward and show that the ball moves westward (perhaps with superimposed inertial oscillations). Calculate the expected westward speed and compare it to the observed. 2) Speed the table up to 3500 and show that the ball moves eastward. Compare to theory. 3) Because of friction, the ball will spiral inwards or outwards. Explain qualitatively (or quantitatively).