A point on the equator of the Earth, due to its daily rotation, moves at a speed of 0.5 km / s (2πRЗ / (24 • 3600)). The radius of the parallel at latitude φ is less than the radius of the equator by (cos φ) times. Thus, the length of the 60 ° parallel is 2 times less than the length of the equator. Consequently, the linear speed of St. Petersburg is 2 times less than the speed of a point on the equator, i.e. 0.25 km / s.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.