Hi, This is one of the things that confuses me. Assume an object on the surface of the earth has a mass m and F=m*g is the force on it due to the gravity. But also the earth is rotating and although the radius is extremely large compared to the size of the object but it must be affected by this rotation as well, isn't it? This is the part that I couldn't figure out. What is the total force on the body? Is it: (G*m*M/R^2) - (m*v^2/R); obviously first one gravity component and the second one angular acceleration. Thanks in advance.