Why centrifugal force is maximum at equator and what occurs when a surface current hits a continent and changes direction?
At the equator, the centrifugal force is maximum because of the Earth's rotation. When a surface current hits a continent, it can change direction due to the continent's shape and the Coriolis effect.
The equator is moving quickly as the earth's spins, so it has a lot of centrifugal force. In contrast, the poles are not spinning at all, so they have zero centrifugal force. Since centrifugal force points outwards from the center of rotation, it tends to cancel out a little bit of earth's gravity. Since the centrifugal force depends on →R, it is greatest at the equator and zero at the poles. As a result of the centrifugal force, the Earth has become slightly oblate, with an equatorial radius of 6378.1 km that is 0.34% greater than the polar radius of 6356.8 km. Centripetal force Fe=mv2R and the radius of the earth near the poles are less so the centripetal force is maximum near the poles. The centrifugal force for the spinning of earth is maximum at the equator and vanishes at the poles. Thus, the gravitational acceleration (g) is minimum at the equator and it is maximum at the poles. Specifically, Earth rotates faster at the Equator than it does at the poles. Earth is wider at the Equator, so to make a rotation in one 24-hour period, equatorial regions race nearly 1,600 kilometers (1,000 miles) per hour. Near the poles, Earth rotates at a sluggish 0.00008 kilometers (0.00005 miles) per hour. The earth spins at constant rate but rate of movement is different the equator is moving fastest and poles are not moving (ignoring the fact that earth is orbiting the sun). Because of this movement centrifugal force is pulling matter closer to equator which structure outwards giving earth slightly non-spherical shape. At the equator, the circumference of the Earth is 40,070 kilometers, and the day is 24 hours long so the speed is 1670 kilometers/hour (1037 miles/hr). Thus as the spinning speed of earth increases, then g at equator decreases and thus weight of body decreases at equator. An Earth spinning in the opposite direction would have very different atmospheric and ocean currents. Although the global mean temperature would remain almost the same, the major ocean currents would switch from the Atlantic to the Pacific, changing the planet's climate drastically. The product of mass and acceleration due to gravity is the body's weight, and the acceleration due to gravity increases with latitude. The equator has the shortest latitude and the poles have the longest. As a result, gravity-induced acceleration and weight are greatest near the poles and lowest at the equator. Continental Deflections When surface currents meet continents; the currents deflect, or change direction. Currents are also affected by the temperature of the water in which they form. The major wind belts push the water in the surface currents. The water moves in the direction of trade winds: east to west between the Equator and 30°N and 30°S. When surface currents meet continents, they change their direction. Winds, water density, and tides all drive ocean currents. Coastal and sea floor features influence their location, direction, and speed. Earth's rotation results in the Coriolis Effect which also influences ocean currents. Three forces cause the circulation of a gyre: global wind patterns, Earth's rotation, and Earth's landmasses. Wind drags on the ocean surface, causing water to move in the direction the wind is blowing. Earth's rotation deflects, or changes the direction of, these wind-driven currents. The continents act as barriers to surface currents. When a surface current flows against a continent, the current is deflected and divided.
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