Kepler's third law states that the square of the orbital period is proportional to the cube of the semi-major axis of its orbit. In equation form, P^2 / a^3 = constant. For the earth, (1 y)^2 / (1 AU)^3 = 1, so the constant is 1. For a planet 4 AU from the sun:
P^2 / (4 AU)^3 = 1P^2 = 64P = 8 years
Earth was the center of the universe
Answer:
Part a)

Part b)

Explanation:
Part a)
As we know that the acceleration due to gravity is given as



now we know that



now we have


Part b)
As we know that the escape speed is given as



