How long did it take for the flag to rotate once in a full circle?

The time it takes for a flag to rotate once in a full circle depends on the speed of rotation. If the flag rotates at a constant speed, the time can be calculated using the formula: time = 1 / rotational speed. For example, if the flag takes 10 seconds to complete one full rotation, the rotational speed is 1 rotation per 10 seconds, so the time taken for one full rotation is 10 seconds.