Diameter does affect the gravitational force you feel at "sea level", because if the earth's diameter is smaller, then someone standing at "sea level" is closer to the center of the earth. But, if the mass of the smaller "earth" is the same as the larger "earth" then the acceleration toward that body should be the same.
I do not subscribe to the smaller earth theory.
But, if the mass of the smaller "earth" is the same as the larger "earth" then the acceleration toward that body should be the same.
Do you feel the same pull toward the earth when you are near Pluto, as when you are on the beach in Brazil?
From Newton's Universal Gravity Equation:
Newton's Theory of Universal Gravitation states that two objects will attract each other with a force proportional to their masses and inversely proportional to the square of distance between them. The Universal Gravity Equation is:
F = GMm/R²
- F is the force of attraction between two objects
- G is the universal gravitational constant; G = 6.67*10-11 N-m²/kg². The units of G can be stated as Newton meter-squared per kilogram-squared or Newton square meter per square kilogram.
- M and m are the masses of the two objects
- R is the distance between the objects, as measured from their centers
- GMm/R² is G times M times m divided by R-squared
Now -- notice that
1/R-squared term.
Your weight due to the earths gravity varies with:
- Your mass.
- The earth's mass.
- The inverse of the distance between you and earth, squared.
Dinosaurs were confined to the earth's surface. They did not swim deep, climb tall mountains or fly (and even those activities don't change one's elevation all that much.)
If the earth has a smaller diameter, and you're on the earth's surface, then you are closer to the center of the earth, and experience greater gravitational force due to the earth's mass.
Of course, as noted in earlier posts, if the earth is spinning, then some, perhaps even all, of this gravitational force is counterbalanced by a so-called centrifugal force.