Circular Motion

In a circular motion, the distance covered in half revolution is the length of the semicircle: The displacement is the straight line joining the initial and final points, which is the diameter of the circle: Therefore, the ratio of distance covered to displacement is: Thus, the correct answer is .

For a satellite in orbit, angular momentum remains constant if no external torque acts on it. This is due to the conservation of angular momentum in a central force field, such as gravity.