After recently seeing a video of a man doing a loop on a swing, it occurred to me that swinging in that manner is pretty counterintuitive to the things I learned in physics class.
Basically, how do we make it go higher without an external force to push us, and without pushing ourselves off of anything? I’m stuck thinking that you can’t lift a chair that you’re sitting on, so a swing should work the same.
My first thought was it must be something to do with how you generally swing your legs, but in the video I saw, the guy on the swing didnt use his legs in that way at all as he was standing on the seat of the swing.
So, in simple terms what actually is happening there, and where does that momentum come from?
In: 9
You’re right you need to be pushing off something, but it’s just counterintuitive as to what you are pushing off. You are essentially pushing of the bar of the swing using the chain.
It’s easier to visualize when you are already at a bit of altitude. Say at 45 degrees. If you raise your center of gravity a bit you push of the seat. You are accelerating your body toward the bar. Some of that works against gravity, the rest accelerated you sideways.
Then at the dip when the swing is vertical you can reset your center of gravity. Since the swing is straight up and down you resetting your center of gravity doesn’t change the forward and back motion.
It’s also why it’s really hard to start swinging from a dead stop. You need at least a bit of an angle to be transferring force forward or back.
So as long as you can direct force against the seat you can go higher. You legs do this by trying to raise your center of gravity when pulled in, and when standing you can do the same with a bit of a couch, or pulling on the chains with your hands.
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