What would Newton say?
force = mass × acceleration”; but first, he’d want to choose an “inertial frame” within which to do this, since his laws only work in inertial frames. An inertial frame is one in which, if we throw a ball, it moves away from us with constant velocity (i.e. constant speed in a straight line). Since this doesn’t quite happen on Earth, the frame Newton would choose would be something more all-encompassing, outside of Earth. One good approximation would be the frame of the Solar System, within which the Sun is at rest and Earth revolves fairly accurately in a circle around it, once a year. An inertial frame like this is presumably what von Braun is using, because anything noninertial won’t tie in too well with his picture of Earth plus satellite.
