Oh, man. It took me awhile to realize that those aren’t ropes. I was waiting for him to pass horizontal, have them slacken, slam taut, and snap him off.
That thing shouldn’t be filed under humor, but under Terror. And under Blood Sports (which can be defined as any sport in which the participant is in significant chance of getting killed)
I was suprised that he went over backwards, if he had gone over the other way he would have been able to keep on pumping and just keep on circling the bar faster and faster.
His butt does hang over one side of the swing, but other than that, the physics is symmetric. When he shifts his center of mass towards the center, conservation of angular momentum makes the swing speed up. That works regardless of which way he goes over the top. There’s no reason he couldn’t do faster and faster loops in either direction.
Think of an ice skater speeding up a spin by moving his arms in. Clockwise or counter-clockwise, it works either way.
I say all this as an armchair physicist who is not about to do a real-world demonstration.
Well, as a person who has swung and having observed a number of novice swingers become adept, I think you have neglected a force calculation. When facing forward and traveling in that direction and pumping you have an acceleration of input of energy. The back swing is almost a rest stroke, especially standing, where you try to minimize your drag. The most intense energy release is at the top of forward swing, reminiscent of high bar jumpers’ final kick over the bar.
If you don’t believe me, watch the video. The guy goes from almost vertical on the last forward swing, to just past vertical on the last back swing. Obviously he gained some momentum on the last back swing.
Drag is the same in both directions, assuming there is no wind. Now it may be that we tend to settle into a natural rhythm where we pick up momentum on the forward swing and coast through the back swing.
I’m tempted to find a playground and see if I can pump the back swings and coast through the forward swings.
Upon review, I see that when he gets to the top of the forward swing he keeps his body in alignment with the cords but at the top of the back swing he creates a 15 degree angle with the cords which, when he is above the horizontal, brings him closer to going over in that direction. Also, on the last swing, he uses his arms to actually pull himself over.
This may be because of the range of movement limits of the arm and shoulder joints.
But if I want to go over facing forward so I get a better view, I would have to time that “out of alignment” motion towards a backwards over the top until after the change of direction occurred. This would slow down the entire process, but would it allow control of which direction to circle?
October 13th, 2008 at 6:31 am
Oh, man. It took me awhile to realize that those aren’t ropes. I was waiting for him to pass horizontal, have them slacken, slam taut, and snap him off.
That thing shouldn’t be filed under humor, but under Terror. And under Blood Sports (which can be defined as any sport in which the participant is in significant chance of getting killed)
October 13th, 2008 at 9:12 am
It does have a certain Stephen King quality about it. I can’t watch it without feeling like I am on a swing about to lose control.
October 13th, 2008 at 4:02 pm
I was suprised that he went over backwards, if he had gone over the other way he would have been able to keep on pumping and just keep on circling the bar faster and faster.
October 13th, 2008 at 6:22 pm
His butt does hang over one side of the swing, but other than that, the physics is symmetric. When he shifts his center of mass towards the center, conservation of angular momentum makes the swing speed up. That works regardless of which way he goes over the top. There’s no reason he couldn’t do faster and faster loops in either direction.
Think of an ice skater speeding up a spin by moving his arms in. Clockwise or counter-clockwise, it works either way.
I say all this as an armchair physicist who is not about to do a real-world demonstration.
October 18th, 2008 at 6:03 am
Well, as a person who has swung and having observed a number of novice swingers become adept, I think you have neglected a force calculation. When facing forward and traveling in that direction and pumping you have an acceleration of input of energy. The back swing is almost a rest stroke, especially standing, where you try to minimize your drag. The most intense energy release is at the top of forward swing, reminiscent of high bar jumpers’ final kick over the bar.
October 18th, 2008 at 8:03 am
If you don’t believe me, watch the video. The guy goes from almost vertical on the last forward swing, to just past vertical on the last back swing. Obviously he gained some momentum on the last back swing.
Drag is the same in both directions, assuming there is no wind. Now it may be that we tend to settle into a natural rhythm where we pick up momentum on the forward swing and coast through the back swing.
I’m tempted to find a playground and see if I can pump the back swings and coast through the forward swings.
October 19th, 2008 at 5:09 am
Upon review, I see that when he gets to the top of the forward swing he keeps his body in alignment with the cords but at the top of the back swing he creates a 15 degree angle with the cords which, when he is above the horizontal, brings him closer to going over in that direction. Also, on the last swing, he uses his arms to actually pull himself over.
This may be because of the range of movement limits of the arm and shoulder joints.
But if I want to go over facing forward so I get a better view, I would have to time that “out of alignment” motion towards a backwards over the top until after the change of direction occurred. This would slow down the entire process, but would it allow control of which direction to circle?