The Earth's rotation does not directly influence its gravitational attractive force. Gravity is primarily determined by the mass of an object and the distance between objects. The force of gravity between two objects depends on their masses and the distance separating them, as described by Newton's law of universal gravitation.
However, the Earth's rotation does have some secondary effects on the distribution of mass and the shape of the planet, which can have indirect implications for gravity. These effects include:
Centrifugal Force: Due to the Earth's rotation, an outward centrifugal force is generated near the equator. This force counteracts the gravitational force and causes a slight bulge around the equatorial region. As a result, the Earth is not a perfect sphere but rather an oblate spheroid, slightly flattened at the poles and bulging at the equator. The variation in the Earth's shape affects the distribution of mass, which can influence the gravitational field strength at different locations.
Geopotential Surface: The Earth's rotation affects the shape of the geopotential surface, which is a hypothetical surface that approximates the Earth's gravitational field. The geopotential surface is not a perfect sphere due to the centrifugal force caused by rotation. Instead, it deviates from a spherical shape, resulting in gravitational anomalies across the Earth's surface. These anomalies can cause slight variations in the strength of the gravitational field at different locations.
It's important to note that the effects of Earth's rotation on gravity are relatively minor and generally not noticeable in everyday life. The force of gravity is primarily determined by the mass of the Earth and the distance between objects, as described by the universal law of gravitation.