The Physics of "Launching" Yourself at Someone

#26
#26
Sheik Yerbouti said:
Well, it might be more dangerous to the launching player. Remember when Travis Henry dove over the pile in that Vandy game (I think) at Neyland and landed on his head? Pretty scary moments there. I remember how quiet Neyland got.
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but that was a freak accident from landing wrong. to use that as an example would mean to take football and play it in zero gravity.
it seems the issue is that people are trying to take ALL the risk from football (sports) and make the 100% safe.
its impossible.
there is risk in every aspect of life (come more than others) and i thinkplayers should be aware and taught the right way to play. big hits are part of the game launching or not
 
#27
#27
txvolsfangatorh8r said:
but that was a freak accident from landing wrong. to use that as an example would mean to take football and play it in zero gravity.
it seems the issue is that people are trying to take ALL the risk from football (sports) and make the 100% safe.
its impossible.
there is risk in every aspect of life (come more than others) and i thinkplayers should be aware and taught the right way to play. big hits are part of the game launching or not
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Maybe, but what is the rate of "freak accidents" in launch situations as compared to non-launch situations? Now we need a statistician, a historian and a physicist. Good grief!
 
#28
#28
It's all about getting some extra velocity on the hit. While you don't have the ability to continue driving forward on a launch, the extra velocity you get by basically springboarding yourself off of the ground adds to the total kinetic energy you have. The more energy you have, the easier it is to affect another system (i.e. send another player flying). In essence, this should allow you to deliver a hit with more "force"... But it all depends on if you get extra speed from flinging yourself off the ground (and that's probably debatable).
 
#29
#29
No, there may be a small amount of energy just from the fact that you can fully extend your legs during the "launch," but once again all that energy is depleted very quickly once you make contact with the other player. If you stay on the ground and drive with your legs, you can deliver a lot more energy through the process of the hit.

I'm still not convinced that this "launching" rule even exists. I think it may be a misinterpretation, because it doesn't make sense as a rule.
 
#30
#30
hmanvolfan said:
That's what I'm seeing happening in the future. The pussification of football marches on... :p
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I like this term...pussificatin of football. :lolabove:

Back to the topic. Launching yourself at a ballcarrier or receiver is a last ditch effort. Unfortunately it is used too often. A defensive player has to decide, within a split second, whether they will be able to catch up to the player to tackle him properly or is he going to dive at the player. It depends alot on positioning of the defensive player and the timing of the ballcarrier/receiver. When it comes to hitting a receiver, obviously the idea is to hit the player as the ball gets to the receiver to separate the two. I believe it is a legitimate tactic depending on your positioning as a defensive player.

I will say that our secondary seems to use it way too often when they should be taking better angles, wrapping up, and driving through. It seems that many of them either fear larger ball carriers, are taught to do this, or their not putting to practice what they are coached.
 
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#31
#31
Some interesting tidbits.

"The kinetic energy of an object is the energy which it possesses due to its motion.[1] It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes. The same amount of work is done by the body in decelerating from its current speed to a state of rest."

"Mass times speed (magnitude of velocity) equals the magnitude of momentum."

So the idea being that you can temporarily increase your speed (magnitude of velocity) to increase your kinetic energy, which is built up, to deliver a more devastating blow. So I guess the question comes down to whether the defender can increase his individual speed by launching at a ballcarrier/receiver. You don't see larger defenders doing this as much because it takes a greater effort(work) to accelerate a body with as much mass. I'm assuming that there is a range of weight in which it is beneficial to launch yourself and that this also relative to your capability in your leg muscles to accelerate faster than just running?

All speculative of course.
 
#32
#32
Probably has nothing to do with physics...its just when you launch yourself at somebody there is a higher probability of striking the head or kneck area of the opposing player.

I'm an engineer by education. Traditionally force is calculated by:

F = ma (force = mass * acceleration)

....but actually, if you ask a pure physicist, a more accurate definition of force is

F = (delta p)/(delta t)...(force = change in momentum / change in time)

Depending on the nature of the hit, you may be able to deliver more force if moving fast enough through the air. Couple that with the increased probability of head or neck blows and it is probably the reason they don't want player doing it.

My opinion anyway. Take it or leave it.
 
#33
#33
I hate to say this, because people are thinking very deeply, but this is a very dumb thread.

A dangerous hit is like porn. Hard to define, but you know it when you see it.
 
#34
#34
rjd970 said:
Probably has nothing to do with physics...its just when you launch yourself at somebody there is a higher probability of striking the head or kneck area of the opposing player.

I'm an engineer by education. Traditionally force is calculated by:

F = ma (force = mass * acceleration)

....but actually, if you ask a pure physicist, a more accurate definition of force is

F = (delta p)/(delta t)...(force = change in momentum / change in time)

Depending on the nature of the hit, you may be able to deliver more force if moving fast enough through the air. Couple that with the increased probability of head or neck blows and it is probably the reason they don't want player doing it.

My opinion anyway. Take it or leave it.
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I don't know if the risk of injury is the reason "they don't want the player doing it." If your talking about coaches, they want players tackling with good technique. The NCAA may not like the launching but it's part of the game (atleast for know). Of course, chop blocking used to be a normal part of the game as well but atleast that new rule is not as subjective.
 
#35
#35
WesternKyVol said:
I hate to say this, because people are thinking very deeply, but this is a very dumb thread.

A dangerous hit is like porn. Hard to define, but you know it when you see it.
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It's called intelligent conversation and you just added nothing to it. :thumbsup:
 
#36
#36
Nashvol2 said:
I don't know if the risk of injury is the reason "they don't want the player doing it." If your talking about coaches, they want players tackling with good technique. The NCAA may not like the launching but it's part of the game (atleast for know). Of course, chop blocking used to be a normal part of the game as well but atleast that new rule is not as subjective.
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No disagreement from me. You also have to consider that the person that is launching himself will usually be doing it head first, using the helmet to strike...not good form and significant risk of injury.

I think it is a dumb rule too, but it can be argued.
 
#37
#37
rjd970 said:
No disagreement from me. You also have to consider that the person that is launching himself will usually be doing it head first, using the helmet to strike...not good form and significant risk of injury.

I think it is a dumb rule too, but it can be argued.
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Based on what I have read in the NCAA rulebook, a specific "launching" rule doesn't actually exist. There is the helmet to helmet rule. Launching does increase the chances of hitting head first though.
 
#38
#38
I'm not a Physicist but I have a buddy who is...so I asked him to take a look at the science of launching.....it is really not that complex now that I see it broken down...


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#40
#40
Nashvol2 said:
It's called intelligent conversation and you just added nothing to it. :thumbsup:
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Except sanity. Intelligence does not always equal wisdom.

As far as adding nothing. Your wonderful "kinetic energy" post was just a rehash of American Pig's" post from page 1.

Aside from that post, which established that forward momentum was maintained and upward momentum was destroyed by gravity, what are you guys rambling about?
The breaking news that fat guys have a harder time jumping than skinny guys?
 
#41
#41
WesternKyVol said:
Except sanity. Intelligence does not always equal wisdom.

As far as adding nothing. Your wonderful "kinetic energy" post was just a rehash of American Pig's" post from page 1.

Aside from that post, which established that forward momentum was maintained and upward momentum was destroyed by gravity, what are you guys rambling about?
The breaking news that fat guys have a harder time jumping than skinny guys?
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Just FYI...no one says you have to post in threads you think are dumb. Some obviously think this is a legitimate question.

Thanks for you input.

:hi:
 
#42
#42
WesternKyVol said:
Except sanity. Intelligence does not always equal wisdom.

As far as adding nothing. Your wonderful "kinetic energy" post was just a rehash of American Pig's" post from page 1.

Aside from that post, which established that forward momentum was maintained and upward momentum was destroyed by gravity, what are you guys rambling about?
The breaking news that fat guys have a harder time jumping than skinny guys?
Click to expand...

You are Awesome! No matter what the kids said about you in middle school or how many times they hit you. Remember that always.
 
#43
#43
rjd970 said:
I'm an engineer by education. Traditionally force is calculated by:

F = ma (force = mass * acceleration)

....but actually, if you ask a pure physicist, a more accurate definition of force is

F = (delta p)/(delta t)...(force = change in momentum / change in time)
Click to expand...

You stated that and then didn't say how it affects the discussion.

Also momentum is p=mv and mass is constant so delta p = delta v * m. Acceleration = delta v / delta t. Therefore, F = m * delta v / delta t. = m*a

You just quoted the same equation. For the record I always use F = ma. Were you just trying to condescend people with that statement? Using momentum may be more convenient for hydraulics or other fields but it's certainly not the "proper" way as you insinuated. Nor does it matter.
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#44
#44
Thrasher865 said:
You stated that and then didn't say how it affects the discussion.

Also momentum is p=mv and mass is constant so delta p = delta v * m. Acceleration = delta v / delta t. Therefore, F = m * delta v / delta t. = m*a

You just quoted the same equation. For the record I always use F = ma. Were you just trying to condescend people with that statement? Using momentum may be more convenient for hydraulics or other fields but it's certainly not the "proper" way as you insinuated. Nor does it matter.
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Are you just trying to be condencending by proving to everybody you can do algebra and dimensional analysis? I was just stating that looking at this by change in momentum rather than m*a might offer a different viewpoint as to why launching might be more violent. It's obviously all the same concept just presented differently.

Maybe the "more accurate" was a poor choice of words...but with most of the guys I went to school with that are classical physicists, momentum delta over delta time is the more applicable way. F = ma is more understandable.
 
#45
#45
There's not a rule against "launching" in the NCAA rulebook...........but I would say you do not lose as much velocity because your body becomes a spear. you do, however, lose complete control of what your body does to the ball carrier. This could cause you to have head to head contact which there is a rule against in the NCAA rulebook.
 
#47
#47
All it took was one announcer to use the word "launch". Things really took off from there.
 
#48
#48
I've never been more proud of my TN brothers. Do you really think they would have this conversation on a Bama board?
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#49
#49
rjd970 said:
Probably has nothing to do with physics...its just when you launch yourself at somebody there is a higher probability of striking the head or kneck area of the opposing player.

I'm an engineer by education. Traditionally force is calculated by:

F = ma (force = mass * acceleration)

....but actually, if you ask a pure physicist, a more accurate definition of force is

F = (delta p)/(delta t)...(force = change in momentum / change in time)

Depending on the nature of the hit, you may be able to deliver more force if moving fast enough through the air.
Click to expand...

Nicely done. :thumbsup:
 
#50
#50
This really isn't a physics problem. It is a rule and location problem. Like the NFL, the NCAA prohibits initial contact above the shoulders on a defenseless receiver. Launching happens all the time in football, particularly as linebackers come in to hit between the tackles. The problem with Janzen's hit was that by launching himself he initiated contact above the shoulder's on a defenseless receiver.
 
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