Question

If the radius of the earth were doubled while at the same time its mass remained constant, by what factor would this change its acceleration due to gravity at the surface?

Answer 1

a = G M / R^2 acceleration at surface

a2 / a1 = (R1 / R2)^2 = (1/2)^2 = 1/4

The acceleration would be 1/4 of its original acceleration