How to Calculate the Gravitation Force from a Black Hole

-- CHIRAG | December 27, 2020
EHT image of event horizon in the central supermassive black hole of M87

Question:

Could you please tell me what will be the distance from the singularity of a black hole to a point outside of the black hole where we will not feel its gravitational pull. Will it be any multiples of Schwarzschild radius?

-- CHIRAG

Answer:

Newton’s law of universal gravitation is as follows:

F = GMm/r^2

where F is the gravitational force (in Newtons), G is the gravitational constant (6.674×10^(-11) N·m^2/kg^2), M and m are the masses, in kilograms, of two objects experiencing a gravitational attraction from the other, and r is the distance, in meters, between the two masses M and m.  You can use a nice gravitational force calculation tool to calculate when the force from a black hole would be so small so as to be undetectable.  The Schwarzschild radius corresponds to the size of the event horizon in a black hole.

-- Jeff Mangum