Final answer:
The effective value of gravity at 45° North on Earth is directed downward towards the Earth's center while also slightly towards the Earth's axis of rotation due to centrifugal effects of the Earth's rotation.
Step-by-step explanation:
The direction of the effective value of gravity at a latitude of 45° North on the Earth points directly toward the center of the Earth. This is true because gravity acts as a centripetal force, pulling objects towards the Earth's center of mass. However, the actual acceleration due to gravity experienced by an object also depends on the Earth's rotation, which causes a slight reduction in the net gravitational acceleration due to the centrifugal effect. Thus, at 45° latitude, the acceleration due to gravity is slightly less than the standard gravitational acceleration of 9.81 m/s2, though this is a small effect compared to the primary downward pull toward the center of the Earth. At the poles, the effect of Earth's rotation is least pronounced, and as one moves towards the equator, this effect increases. The effective value of gravity is therefore directed downward and slightly towards the Earth's axis of rotation from the point of observation.