Why do different parts of earth rotate at different speeds?

Different parts of the Earth rotate at varying speeds primarily due to its spherical shape. The equator, being the widest part, travels at a faster linear speed (about 1,670 kilometers/hour) compared to areas near the poles, which move much slower because they cover less distance in the same amount of time. This difference in rotational speed is a result of the conservation of angular momentum, where the rotational speed is greatest at the equator and decreases toward the poles. Additionally, the Earth's axial tilt and rotation dynamics contribute to these variations.