Anewly discovered planet has twice the mass of the earth, but the acceleration due to gravity on the new planet’s surface is exactly the same as the acceleration due to gravity on the earth’s surface. what is the radius rp of the new planet in terms of the radius r of earth?

R p=√2 R

Explanation:

If we take the radius of the earth to be R . And the radius of the new planet as R p. Then we mass of the new planet be twice that of the Earth. But the acceleration form the gravity of these planets will be the same. Thus the radius of the new planet would be equal to R p=√2 R.