4 ms·
A swing works by moving you back and forth relative to the Earth (and moving the Earth back and forth slightly as well, in the opposite direction, more or less.
by phyzome 7y ago
A swing works by moving you back and forth relative to the Earth (and moving the Earth back and forth slightly as well, in the opposite direction, more or less.) The you + Earth system is not actually going anywhere. :-)
- z3t4 7y agoSo you need to leave something behind in order to go somewhere? But it would only be relative to the thing I left behind? But then there is some "special" relativity that applies everywhere?
- phyzome 7y ago> So you need to leave something behind in order to go somewhere? As a definition, no. But no one has been able to figure out reactionless propulsion; as far as anyone can tell, the only way to accelerate in space is to throw something in the opposite direction (matter or light).
- z3t4 7y agoIf you tie a rope to a hammer, then spin it around as fast as you can like a hammer thrower, and drop it. Wouldn't the breaking force propel you in the same direction your let go of the hammer?
- antonvs 7y agoIf you're in zero g and not on a surface with friction to push against, you're not going to be able to do what a hammer thrower can do standing on Earth. But, if you provide some momentum to an object like a hammer and release it, you will move. That goes back to "you need to leave something behind in order to go somewhere."