The radius of Earth is 6,378 km. The force of gravity on a 1 kg ball at Earth's surface is 9.8 kg m/s². What is the force of gravity on this same ball when the ball is located 12,756 km from Earth's center? Hint: G = 6.67 10^-11 m³/s²/kg A) 2.45 kg m/s² B) 4.9 kg m/s² C) 9.8 kg m/s² D) 19.6 kg m/s² E) 39.2 kg m/s²

Question

Quizplus · Accepted Answer

The force of gravity decreases with the square of the distance from the center of the Earth. At 12,756 km, the distance is twice the Earth's radius, so the force is (1/2^2) * 9.8 = 2.45 kg m/s².

The Radius of Earth Is 6,378 Km