I'm learning coriolis effect on Winds moving from equator towards North pole. This is for geography.
Question: Why is coriolis force stronger for winds having larger speed(larger component of Northward velocity)?
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2 Answers
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The reason the coriolis effect (for north-south direction) is proportional to velocity is related to the concept of conservation of angular momentum.
The air mass of the Earth is co-rotating with the Earth. That means the applicable momentum is angular momentum instead of linear momentum.
(Incidentally, the general coriolis effect is the same for any direction of motion. That is: the effect is not exclusive to north-south motion.)
In the image the point where the vertical and horizontal axis cross coincides with the center of circumnavigating motion.
The dotted line represents the trajectory of an object that is circumnavigating counterclockwise, and being pulled closer to the axis of circumnavigation.
In the diagram the centripetal force is decomposed in two perpendicular components, one tangent to the instantaneous velocity, and one perpendicular to the instantaneous velocity.
The component acting tangent to the instantaneous velocity causes angular acceleration. The rate of angular acceleration is proportional to the radial velocity. In the case of the motion presented in the diagram: if the radial velocity is larger then the object is spiralling in at a steeper angle, which means the tangential component (of the centripetal force) is larger, causing larger angular acceleration.
About conservation of angular momentum.
Kepler's law of areas anticipated the later recognition of conservation of angular momentum. In the Principia Newton demonstrated a generalized area law, showing that it obtains for any central force.
Further reading:
Jan 2021 answer (by me) to a question titled 'Intuition for angular momentum': presentation of Newton's generalized area law.
On my own website:
The coriolis effect in meteorology.
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$\begingroup$ Thanks. But still I didn't get it. 🙃 $\endgroup$ Commented Dec 11, 2023 at 16:10
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If you think about it, more wind speed equals more force when wind hits the ground or anything else. This will mean more energy for a lets say 50km/hour than a 25km/hour wind. This then means more rebound and more other stuff that you know that causes the effect, which means more speed (kinetic energy) fed back into the wind when the effect takes place.
