Gravitational effects from large bodies of mass are nonexistent. These golden retrievers are in deep, deep space. They are named Mr. Squabbles, Alfredo, and Billy. Mr. Squabbles is suspended in space (at rest)--he has not been acted upon by any force. (If that's possible.) Alfredo has a rocket booster, and assuming deep below him in space there is marked pavement (something to aid in measuring distance--it can be grass, whatever), he is moving at 100 mph. Billy has a rocket booster and is going around in circles (around Alfredo and Mr. Squabbles) at varying rates (35-40, 45-50, 20-25mph). My question: Will Billy, who is "accelerating", feel a "jerk" when he changes his rates of motion ("accelerates" of "decelerates"? If so, why? I know we--or the pups--can SEE the relative motion, but in deep space, how can any of these goldens actually feel the difference between being at rest or accelerating?