Final answer:
The acceleration due to Earth's gravity is less at a point three Earth radii away compared to the acceleration at the Earth's surface, due to the inverse square law of universal gravitation.
Step-by-step explanation:
When comparing the acceleration due to Earth's gravity at a point three Earth radii away from the center of the Earth to that at the Earth's surface, we can apply Newton's law of universal gravitation. This law tells us that the force of gravity, and hence the acceleration it causes, decreases with the square of the distance from the center of the mass causing the gravitational pull.
At the surface of the Earth, this acceleration is approximately 9.80 m/s². However, at three Earth radii away, the acceleration would be (1/3)², or 1/9th of that at the surface, because the gravitational acceleration is inversely proportional to the square of the distance from the center of the Earth.
Therefore, the acceleration due to gravity at a point three Earth radii away from the center is lesser than the acceleration at the Earth's surface.