The Coriolis Effect Elliott Chick Current University of

The Coriolis Effect Elliott Chick Current University of Exeter MPhys Undergraduate

What is it? �The Coriolis effect is the apparent deflection of an object in a rotating reference frame. �Gaspard-Gustave Coriolis was first to consider this supplementary force. �When Newton's laws of motion are applied in a rotation frame of reference, other forces appear. �These forces are “Fictitious forces” and are used as correction factors for the simple application of Newton’s laws in a rotating system.

Newton's Laws in a rotating reference frame. �

Newton's Laws in a rotating reference frame. �

The Coriolis force �

An example… • One of the Coriolis effect’s most common appearance is in ballistics. • Target: Ciudad Real Madrid 40. 479167 N, 3. 611667 W • Distance from Physics Building: 1141 km • Tomahawk missile • Average speed = 244. 4 m/s (sub sonic) • Effective range = 2500 km • ω of earth = 7. 27 x 10 -5 rads/s (http: //toolserver. org/~geohack/geohack. php? pagename=Ciudad_Real_Madrid&params=40_28_45_N_03_36_42_W_type: landmark) (http: //www. nhc. noaa. gov/gccalc. shtml) (http: //en. wikipedia. org/wiki/Tomahawk_(missile)) (http: //hypertextbook. com/facts/2002/Jason. Atkins. shtml) http: //www. europemapofeurope. net/europemap-of-europe-large-2008 -muck-hole. jpg

An example… �

The Experiment �The aim of this experiment was to demonstrate the Coriolis acceleration in a rotating reference frame, and showing that the Coriolis acceleration is proportional to the angular velocity of the rotating reference frame. �Apparatus used: (From experiment ME 06) �Glass turntable (Connected to DC power supply) � Covered with paper �Metal ramp �Ball bearing

Experimental setup

Experimental method �Find the velocity of the ball bearing �Time taken to travel between 2 points �Measure the angular frequency of the turntable �Measure amount of rotations and time taken, use rotations/time to work out revolutions per second �Multiply by 2π to find the angular frequency of the turntable

Experimental method continued �Coat the ball bearing in a layer of ink �Place on ramp, with quick release in place �Start up the turntable �Release the ball �The ball will leave behind a trail of dots, allowing easy observation of the path of the ball

Analysis �

Results 1 0. 2 Demonstration of repeatable results for ω = 1. 2 rads/s 0. 18 0. 16 Displacement (m) 0. 14 0. 12 0. 1 0. 08 0. 06 0. 04 0. 02 0 0 0. 05 0. 1 Time (s) 0. 15 0. 25

Results 2 0. 5 ω = 1. 2 rads/s 0. 4 Velocity (m/s) 0. 3 0. 2 0. 1 0 -0. 05 0 -0. 1 0. 05 0. 1 Time (s) 0. 15 0. 2

Results 3 0. 9 ω = 1. 67 rads/s 0. 8 0. 7 Velocity (m/s) 0. 6 0. 5 0. 4 0. 3 0. 2 0. 1 0 -0. 05 0 -0. 1 0. 05 0. 15 Time (m/s) 0. 25 0. 3

Results 4 ω = 0. 55 rads/s 0. 35 0. 3 Velocity (m/s) 0. 25 0. 2 0. 15 0. 1 0. 05 0 -0. 05 0. 15 Time (s) 0. 25 0. 35

Conclusions �The Coriolis effect can be easily proven using this experimental method �From my results I can see that the Coriolis acceleration is proportional to the angular velocity of the rotating reference frame. �The velocity was kept constant, thus the only factor effecting the Coriolis acceleration was ω showing its proportionality.