Kepler's laws of planetary motion of solar system body number "i" is, according to Newton's laws: where formula_72 is the mass of body "j", formula_73 is the distance between body "i" and body "j", formula_74 is the unit vector from body "i" towards body "j", and the vector summation is over all bodies in the world, besides "i" itself. In the special case where there are only two bodies in the world, Earth and Sun, the acceleration becomes which is the acceleration of the Kepler motion. So this Earth moves around the Sun according to Kepler's laws. If the two bodies in the world are
Three Laws of Robotics to understand when they are causing pain or injury and know to stop. Many are constructed with physical safeguards such as bumpers, warning beepers, safety cages, or restricted-access zones to prevent accidents. Even the most complex robots currently produced are incapable of understanding and applying the Three Laws; significant advances in artificial intelligence would be needed to do so, and even if AI could reach human-level intelligence, the inherent ethical complexity as well as cultural/contextual dependency of the laws prevent them from being a good candidate to formulate robotics design constraints. However, as the complexity of robots has increased, so