Action = reaction. Then why can I get a swing to move?

Question

How is this possible scientifically speaking?

Answer 1

Action/reaction doesn't really have to do with this at all. All it means is that whatever force I exert on the swing, the swing exerts on me right back. My motion looks at all the forces on me, not the forces I exert on other things. So if I can rig it so that the net force of the swing on me is non-zero, I'll move.

So, I move so that the swing chains are at a slight angle from the vertical because my center of mass is not in line with the chains. Then I quickly change my shape (by bending my legs) so that my center of mass is no longer directly below the pivot point, and there's now a net force on me. That'll get me started, and from there it's a matter of resonating with the swing frequency to make sure that the energy I use to move my body around goes into moving my center of mass more.

Answer 2

For every action, there is an equal and opposite reaction. Is that what you're going for? That's not exactly how it's worded, but close enough.

Are you talking about a swing like the ones on a playground? Were you standing behind it or sitting on it? If standing, did you pull it back and up, then let go? If sitting, did you push back with your feet against the ground, then tuck them under so they wouldn't get in the way as you went forward? Did you use your arms to pull tension on the chains that hold the swing and keep the momentum going?

If you did all these things, and the swing still didn't move, you need to get someone with a video camera and do it again. This would defy the laws of physics.

Answer 3

The force of the action and reaction are not on the same object.
If you press on a wall, the wall presses on your hand. That is why you can punch through a wall...you push on the wall, and the wall slows down your fist...and it might not slow it down enough.

In the case of a swing, you exert force on the swing, and the swing exerts force against you. Now, it is true that much of the force you exert against the swing is eventually exerted back to you, but not all of it is. Some is transmitted to the chains and poles and ground, etc. [Note, if you tried to swing on a frictionless plane, you would have a much harder time!]

The part of your force that is not sent back at you [which equals the force that got transmitted to the chassis/ground] is what lets you swing.

Answer 4

If you pull a pendulum (a tiny swing), that is your action.

Answer 5

i did not get ur question...plz explain