Answer:
2640R where R = Radius of earth
Explanation:
Mass of Sun = 333000 of mass of Earth
Mass of rogue black hole (body) = 21 of mass of sun
So, mass of the body = 21 * 333000 of mass of Earth
Mass = 6993000 of mass of Earth
The gravitational attraction force between two point masses is directly proportional to the product of their masses and inversely proportional to the square of their separation distance
Mathematically,
M1 * (R2)² = M2 * (R1)²
Where M and R represents mass and radius
Make R2 the subject of the formula
R1 = SQRT ((M1 * R2²)/(M2))
R1 = R2 * SQRT(M1/M2)
Where R2 represents radius of Earth
M1 and M2 represents mass of object and mass of Earth respectively
M1 = 6993000* mass of Earth
So, equation becomes
R1 = R2 * SQRT(6993000 * M2/M2)
R1 = R2 * √6993000
R1 = 2644.4281R2
R1 = 2640R2 -------- to 3 significant figures
So, the distance of the Black hole from the centre of the earth is 2640R