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AmbukAmbuk
3/23/2012 4:31am,
Are there any boxer that have enough power to make a heavy bag, weighing 400lb or more, fly over long distances? I think HW boxers like Foreman and Tyson could make a 400 pound bag flying into ceiling and thump it, much like the kick that have been done by Bruce Lee on a 300lb bag. But I'm sceptical about Bruce Lee feats because there are only anecdotal evidences from his friends. This is from Bob Wall interview,

'Bob Wall: And so I went as a joke, made him a 300 pound bag. I don’t think there’s a bag bigger than that. And so I stuffed it and called Bruce up in Bel Air and he had a Porshe, and I said “Hey Bruce, why don’t you come on down, I made you a man-sized bag” and he came and Joe and a bunch of our students all hid, I got on the phone, pretending to be on the phone, and I said “Yeah Bruce, go ahead and throw it in the back, its in there hanging up” and so he walked in and the expression on his face would have been great to have on film, and we all fell over when he saw the size of bag…

MPM: (laughs)

Bob Wall: …but he wouldn’t allow us to let him think it was a joke

(at this point Bob gets another call but quickly returns)

It was a friend of mine but I told him I’m in the middle of an interview so anyway we all popped out laughing and Bruce kick it once and fell over and then we helped him take it over to his place and hung it up in the garage and then he went over and kicked it and it broke the whole structure of the garage!

MPM: Wow!

Bob Wall: And so he had Herb (Jackson) come over and redo the whole garage and I’ll tell you, two months later, I saw him and he could kick the heck out of the bag!'

Actually, did the bag really hit the ceiling or because of the bag weight, then the whole structure of the garage broke. It seems like nonsense to me.

Then this is Wally Jay's quote about Bruce Lee,

"I last saw Bruce after he moved from Culver City to Bel Air. He had a big heavy bag hanging out on his patio. It weighed 300lbs. I could hardly move it at all. Bruce said to me "Hey, Wally, watch this" and he jumped back and kicked it and this monster of a heavy bag went up to the ceiling, Thump!!! And came back down. I still can't believe the power that guy had".

I think the bag maybe only weigh at 100-200. Perhaps. But, just assume that Lee's feat is indeed real, do you know any boxer or MMA fighter that could perform such a feat? I think Tyson with his 1800 psi punch can make a 350 pound bag flying as much as Lee kick the 300lbs bag, if not much better.

Matt Phillips
3/23/2012 6:27am,
If you hit the bag properly, it will fold. If it's swinging a lot, you're doing it wrong.

nils
3/23/2012 8:11am,
To answer this question, we need do employ the dark powers of MATH *imagine thunder here*.

Your question in detail: When somebody hits a heavy bag with the mass of 400lbs (181,2kg) and a lenght of ca. 1,5m plus 30cm rope and a radius of 15 cm, how hard will he need to punch to let it swing to the ceiling?

For the following calculation, friction is deemed negligible. Also we assume that the amount of energy which deforms the bag is negligible (so the bag is tightly packed), and that the bag is homogenously packed.
Furthermore, the bag will be punched on the lower end, making this feat easier.

While the bag is in it´s highest state (at the ceiling), it has a higher potential energy than while it hangs down.
The difference of both energys will be the energy you have to transmit to the bag.

The potential Energy on the up-state is m*g*h. But since the bag won´t be pushed flat on the ceiling, it´s m*g*(h-r).

m=mass; g=gravitational acceleration, h=height of bag plus ropes; r=radius of the bag; l= length of the bag without ropes

The Energy on the down-state is m*g*0,5*l.
0,5 because the mass is homogenously distributed in the bag, instead of all being on the downside of it.

E1-E2 equals 1600 Joule, which is the energy you need to transmit.

To get an understanding of that dimension, let´s take an example: Vitali Klitschko weighs in at 113kg. In a strong standing-punch, around 70% of the body-weight leans into the punch.
The formula for kinetic energy is:
E=0,5*m*v^2

repositioned to v; 70% included:

v=Squareroot(2*E/70%*m)

results in a speed of 6,4 metres per second. Which is not hard to do.

You see here, that in theory, this is not difficult. The problem is that a huge part of the energy is transmitted to warmth because of the internal movements of the filliing of the bag.

In Bruce Lees example you brought up, it is described that it was a homemade bag which probably was ridiciously tight-packed. Because of that, the energy-loss by internal movement and the bag-deformation would have been greatly decreased.

Furthermore, I suppose it was on of those Bruce Lee-Trademark jumping sidekicks, which had the tendency to shove.

So, in conclusion: with such a bag, you could do it.

Scrapper
3/23/2012 8:29am,
To answer this question, we need do employ the dark powers of MATH *imagine thunder here*.

Your question in detail: When somebody hits a heavy bag with the mass of 400lbs (181,2kg) and a lenght of ca. 1,5m plus 30cm rope and a radius of 15 cm, how hard will he need to punch to let it swing to the ceiling?

For the following calculation, friction is deemed negligible. Also we assume that the amount of energy which deforms the bag is negligible (so the bag is tightly packed), and that the bag is homogenously packed.
Furthermore, the bag will be punched on the lower end, making this feat easier.

While the bag is in it´s highest state (at the ceiling), it has a higher potential energy than while it hangs down.
The difference of both energys will be the energy you have to transmit to the bag.

The potential Energy on the up-state is m*g*h. But since the bag won´t be pushed flat on the ceiling, it´s m*g*(h-r).

m=mass; g=gravitational acceleration, h=height of bag plus ropes; r=radius of the bag; l= length of the bag without ropes

The Energy on the down-state is m*g*0,5*l.
0,5 because the mass is homogenously distributed in the bag, instead of all being on the downside of it.

E1-E2 equals 1600 Joule, which is the energy you need to transmit.

To get an understanding of that dimension, let´s take an example: Vitali Klitschko weighs in at 113kg. In a strong standing.punch, around 70% of the body-weight leans into the punch.
The formula for kinetic energy is:
E=0,5*70%*m*v^2

repositioned to v:

v=Squareroot(2*E/70%*m)

results in a speed of 6,4 metres per second. Which is not hard to do.

You see here, that in theory, this is not difficult. The problem is that a huge part of the energy is transmitted to warmth because of the internal movements of the filliing of the bag.

In Bruce Lees example you brought up, it is described that it was a homemade bag which probably was ridiciously tight-packed. Because of that, the energy-loss by internal movement and the bag-deformation would have been greatly decreased.

Furthermore, I suppose it was on of those Bruce Lee-Trademark jumping sidekicks, which had the tendency to shove.

So, in conclusion: with such a bag, you could do it.

Remember impulse as well, you are attempting to impart a change in momentum!

nils
3/23/2012 8:54am,
Remember impulse as well, you are attempting to impart a change in momentum!

You could also do the calculation based on impulse, but the transformation of static/dynamic states will get a whole lot more complicated.

Since it´s safe to assume that a well rounded puncher will transform most of the accumulated energy into the bag (i.e. he doesn´t slip off or bounce back), and since the bag is heavier than the person hitting it, I believe we do not need to use impulse.

On the other hand, calculating the impulse would render information about the speed of the bag. If you would like to calculate more detailed (including deformation or friction), this would be neccessary.

Hiro Protagonist
3/23/2012 9:25am,
I don't know about the physics, but if you want to do it...

Try the Supersoldier Program.


http://www.youtube.com/watch?v=kTz6jvJpMIg

nils
3/23/2012 9:28am,
I don't know about the physics, but if you want to do it...

Try the Supersoldier Program.


If you´re a soldier, you might consider shooting at the bag with hollow-point-bullets.

AmbukAmbuk
3/23/2012 9:34am,
Bob Wall said about the 300lb bag that Bruce Lee kicked, 'It was a friend of mine but I told him I’m in the middle of an interview so anyway we all popped out laughing and Bruce kick it once and fell over and then we helped him take it over to his place and hung it up in the garage and then he went over and kicked it and it broke the whole structure of the garage!'

Actually what make the garage to collapsed? Is it because of the bag weight, or the bag really flying into and then thumping the ceiling really hard until the whole structure of the garage broke? I believe this is an exaggeration.

BackFistMonkey
3/23/2012 9:39am,
If you´re a soldier, you might consider shooting at the bag with hollow-point-bullets.


How about a ball round ...

nils
3/23/2012 9:55am,
Actually what make the garage to collapsed? Is it because of the bag weight, or the bag really flying into and then thumping the ceiling really hard until the whole structure of the garage broke? I personally think that this is an exaggeration.

Assuming this story is correct (which is entirely possible) , it´s a combination of factors.

First of all, the weight pulls at the hanger assembly. Furthermore, the swinging of the bag creates a centrifugal force. The whole energy you transmit by punching/kicking, distributed over the whole pathway (because it´s Energy divided by distance it becomes a force) becomes a factor.

At the point of most force, there were 1111Newton (centrifugal force) plus 1775N = 2886N pulling on the roof.

This corresponds to 294 kg of weight (646lbs).

Combine that with those unstable roofs garages tend to have (since they do not need to support upper floors) and kaboom.
And the garage had to be of unstable build, otherwhise the bag-assembly would just have broke out of the ceiling.

And that´s why you should only trust a hanger-assembly of a heavy bag if you can hang and swing on it.


How about a ball round ...

As long as it has enough force and gets stuck in it, rather than going through, go for it.

I do think that there is need of a new martial art that teaches deadly defence against swinging heavybags.


Calculation of centrifugal force:
F=m*w²*r
w= angular velocity
w²=(v/r)²

F=m*v²/r

r=length Bag+ropes. For v, get impulse

ma*va=mb*vb

vb=ma*va/mb

F=m*(ma*va/mb)²/r

AmbukAmbuk
3/23/2012 10:14am,
Originally Posted by nils

Assuming this story is correct (which is entirely possible) , it´s a combination of factors.

First of all, the weight pulls at the hanger assembly. Furthermore, the swinging of the bag creates a centrifugal force. The whole energy you transmit by punching/kicking, distributed over the whole pathway (because it´s Energy divided by distance it becomes a force) becomes a factor.

At the point of most force, there were 1111Newton (centrifugal force) plus 1775N = 2886N pulling on the roof.

This corresponds to 294 kg of weight (646lbs).

Combine that with those unstable roofs garages tend to have (since they do not need to support upper floors) and kaboom.
And the garage had to be of unstable build, otherwhise the bag-assembly would just have broke out of the ceiling.

And that´s why you should only trust a hanger-assembly of a heavy bag if you can hang and swing on it.

Yes that was I'm thinking the garage must have an unstable build, maybe constructed from wood, having weak structure or something alike. So if it possible to make a heavy bag flying with a single punch, then no doubt that MMA fighter like Brock Lesnar, can make a 400lb bag thump the ceiling with his punch.

nils
3/23/2012 10:16am,
^only if it is so tightly packed that deformation and internal friction don´t matter.

AmbukAmbuk
3/23/2012 10:17am,
http://pics.livejournal.com/dochermes/pic/004dt37b

I think this is the 300lb bag that Bruce used to train his kicks.

AmbukAmbuk
3/23/2012 10:33am,
Do you know any martial artists that can do the same feat? Just askin'.

thrutch
3/23/2012 12:23pm,
AmbukAmbuk seems very interested in other men's bags.

Permalost
3/23/2012 1:04pm,
Do you know any martial artists that can do the same feat? Just askin'.
Well, I don't know any martial artists who kicked Bruce Lee's special heavy bag, so no.