Q4. (a) If r is the radius of the Earth, calculate the value of the Gravitational Potential at a distance of r from the Earths centre. (b) A black hole is defined as a body in space whose escape velocity is equal to or greater than the speed of light. An observed stellar object has a mass equal to 4 x 1030 kg and a radius of 2.9 km. I. Using appropriate physics prove that this stellar object can be classified as a black hole. II. What is the acceleration due to gravity on the surface of the object? (c) A woman is standing on the moon. By what factor would her weight increase if she were standing on the Earth as compared to the Moon?

Q4. (a) If r is the radius of the Earth, calculate the value of the Gravitational Potential at a distance of r from the Earths centre. (b) A black hole is defined as a body in space whose escape velocity is equal to or greater than the speed of light. An observed stellar object has a mass equal to 4 x 1030 kg and a radius of 2.9 km. I. Using appropriate physics prove that this stellar object can be classified as a black hole. II. What is the acceleration due to gravity on the surface of the object? (c) A woman is standing on the moon. By what factor would her weight increase if she were standing on the Earth as compared to the Moon?