The Coriolis force is zero at the equator because the vertical component of Earth's rotation is maximal, but the horizontal component, which deflects moving objects, is zero.
To understand this, let's break it down:
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Coriolis Effect Basics: The Coriolis effect is an apparent deflection of moving objects (like air and water) when viewed from a rotating reference frame, like Earth. It's caused by the Earth's rotation. In the Northern Hemisphere, objects appear to deflect to the right; in the Southern Hemisphere, to the left.
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Earth's Rotation and Latitude: Earth rotates on an axis. The effect of this rotation on a moving object varies with latitude.
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The Key to the Equator: At the equator, the axis of rotation is perfectly vertical. Imagine a spinning globe; a point on the equator is moving sideways, not twisting around the axis. An object moving horizontally along the equator doesn't experience a sideways push relative to the Earth's surface because its initial momentum is already aligned with the Earth's rotation at that point.
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Analogy: Think of a spinning merry-go-round. If you stand at the center and walk outwards, you have to adjust your speed to keep pace. This is like the Coriolis effect at other latitudes. But if you walk around the edge of the merry-go-round, you're already moving at the same speed as the edge, so you don't need to make any adjustments. The equator is similar.
In simpler terms, because there is no turning of the surface of the Earth (sense of rotation) underneath a horizontally and freely moving object at the equator, there is no curving of the object's path as measured relative to Earth's surface. The object's path is straight; that is, there is no Coriolis effect.
