The measurement of 9.81 newtons represents the force of gravity acting on a mass of one kilogram at the surface of the Earth. This value is derived from the acceleration due to gravity, which is approximately 9.81 meters per second squared. The unit of force, the newton, is defined as the force required to accelerate one kilogram of mass by one meter per second squared. In practical terms, if you were to weigh an object that has a mass of one kilogram, the gravitational force pulling it down would be 9.81 newtons. This force is crucial for understanding various physical phenomena, including the behavior of falling objects and the principles of physics related to motion and weight.