Oceanography Exam 3

# Oceanography Exam 3 - Oceanography Exam 3 Waves Part 2...

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Oceanography Exam 3 Waves Part 2 Waves are a very efficient means of transferring energy Internal Waves o Waves are not limited to the ocean surface but can occur anywhere there is an interface in stratified fluids o Occur at the pycnoclne o 30m in height, 0.6 – 0.9 km long o Wave speed depends on density differences o Air/water interface has a large density difference o Waves can have fast speeds o Density differences in the ocean are often very slight o These waves are slower o Wave periods of several minutes, o Possible causes: Current flow over bottom topography Atmospheric pressure changes Turbidity flows Tsunami o Caused by rapid displacement of surface water o Usually vertical movement along a fault or mudslide o Tsunami H is 0.5 – 1.0 m but very long wavelength (200 km) o Everywhere in the ocean a tsunami is a shallow water wave o Half of length = 100 km, deepest part of ocean =11km o Speed = square root of gxd o V= 212 m/sec = 764 km/hr o Deep water: not noticeable to most ships o Shallow water: wave slows and water piles o Wave heights can reach 40 m o Detection – buoys that measure gradual measure in pressure, triggers alert o Effects of shoreline morphology Shallow regions and funnel shaped bays more susceptible o Adaman-Nicobar Earthquake and Tsunami of Dec. 26, 2004 Magnitude 9.1 to 9.3 2 nd largest ever recordered Centered 160 km W of Sumatra Tides Newton’s law of gravitation

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o Every particle of mass in the universe attracts every other particle of mass o Attractive force is : Fg = G(m1m2)/r^2 o M1 and m2 = mass of the particles o G = universal gravitational constant (6.672 X10-11Nm2kg-2) o Gravitation force decreases rapidly with distance Vectors o Direction of arrow indicates direction of force o Length indicates magnitude o Vectors are additive o Sum of two equal vectors pointing in same direction = 2 times the force o Pointing in opposite direction = cancels out o Point at right angles = 1.4X square root of 2 times the force but at 45 degrees The Earth-Moon System o Earth and moon attracted to each other by gravity o Gravitational attraction offset by inertia o Object in motion tends to stay in motion (straight line) o Centrifugal force – apparent force directed away from center of circle o Centripitel force – force that produces uniform circular motion, acts along the radius, toward the center of the circle o Earth and moon work as a single system, center of mass lies within earth but not at center (barycenter), period of 27.3 days o Because of common center of mass, earth rotates eccentrically (wobbles) o Because of eccentric motion, every has centrifugal force, is in the same direction at all points in earths surface o Sum of centrifugal and and gravitational forces = tide-producing force Tidal bulges o Bulge forms nearest moon and opposite moon o Water 90 degrees b/w Grav and centrifugal force almost cancel Gravitational force angled slightly toward equator, creates a depression or
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## This note was uploaded on 02/02/2012 for the course ZOL 353 taught by Professor Idk during the Fall '11 term at Michigan State University.

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Oceanography Exam 3 - Oceanography Exam 3 Waves Part 2...

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