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Q66 (NDA-II/2014) Geography › World Physical Geography › Earth rotation and time Answer Verified

If the length of the Equator is about 40000 km and the velocity of rotation is about 1700 km per hour, what would be the velocity of rotation at the Pole?

Result
Your answer:  ·  Correct: A
Explanation

The Earth's rotational speed varies significantly depending on the latitude. While the Earth has a constant angular velocity (completing one 360° rotation in 24 hours), its linear or tangential velocity is a function of the distance from the axis of rotation. At the Equator, where the radius from the axis is at its maximum, the velocity is approximately 1,670–1,700 km/hr [1]. As one moves toward the poles, the radius of the circle of rotation decreases. The tangential velocity at any given latitude is calculated by multiplying the equatorial speed by the cosine of the latitude [1]. At the North and South Poles (90° latitude), the cosine of 90° is zero. Consequently, the linear distance traveled during a rotation is zero, making the rotational velocity at the poles 0 km/hr [2].

Sources

  1. [1] https://www.britannica.com/science/How-Fast-Does-Earth-Spin
  2. [2] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 2: The Earth's Crust > Longitude > p. 11
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