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BravestDog

How many feet would you have to fall to reach 120mph?

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1. Supposed you jumped off of a building, bridge, cliff, balloon...how many feet would you have to fall before you reach 120mph?

Answer: "A typical skydiver in a spread-eagle position will reach terminal velocity after about 12 seconds, during which time they will have fallen around 450 m (approx 1,500 ft)." Found here: http://en.wikipedia.org/wiki/Free_fall under Examples.


2. People who jump from heights into pools, what are their speeds as they hit the water and how high are they jumping from? Are they reaching speed of 120mph?

Answer: Dana Kunze, Record High Dive holder at 172 feet, tumbling type feet first entry. http://www.youtube.com/watch?v=4uHkyMh9FW4

Still looking for his speed at entry.

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I never took Physics in High School or College and am trying to research these questions that I've asked. Not trying to make things difficult, just asking some simple questions that pop up as I'm thinking about other posts that are somewhat related.

Sometimes, the question if pretty simple. But when you get on Wikipedia, it becomes more complicated to the point where it's confusing, then I return to the forum looking for a simple answer.

Just found the anwer: "A typical skydiver in a spread-eagle position will reach terminal velocity after about 12 seconds, during which time they will have fallen around 450 m (approx 1,500 ft)" at the Wikipedia Free Fall site.

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You are asking for simple answers to non-simple questions (in this thread and others). You might want to review your HS (or college?) physics. You really would have a better understanding if you worked it out yourself.

Here's a good place to start:
http://en.wikipedia.org/wiki/Free_fall

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In the 1st second you will fall about 16 feet. At the two second mark you will have fallen about 64 feet. At the three second mark you will have fallen about 144 feet. At the four second mark you will have fallen about 256 feet. At the five second mark you will have fallen about 400 feet.

I say "about" because I am not taking aerodynamic drag into account.

At the start of your fall, the drag is not significant, As your velocity picks up, it starts to become more and more of a factor.

The total distance (in feet) that you fall in a given number of seconds is about:

16 times the number of seconds times the number of seconds again.

X = .5 x g x t^2

The velocity (in feet per second) would be about 32 times the number of seconds that you fall. Again that's not taking aerodynamic drag into consideration.

V = g x t

If you want to take drag into consideration, you need to know your coefficient of drag, and you need to know how to do calculus; or just look at the chart in Dan Poynter's book.

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In the 1st second you will fall about 16 feet. At the two second mark you will have fallen about 64 feet. At the three second mark you will have fallen about 144 feet. At the four second mark you will have fallen about 256 feet. At the five second mark you will have fallen about 400 feet.

I say "about" because I am not taking aerodynamic drag into account.
____________________________________________________________ Aside from simple drag you also have to consider mass and surface area. I.E. a pound of feathers and a pound of lead.

At the start of your fall, the drag is not significant, As your velocity picks up, it starts to become more and more of a factor.

The total distance (in feet) that you fall in a given number of seconds is about:

16 times the number of seconds times the number of seconds again.

X = .5 x g x t^2

The velocity (in feet per second) would be about 32 times the number of seconds that you fall. Again that's not taking aerodynamic drag into consideration.

V = g x t

If you want to take drag into consideration, you need to know your coefficient of drag, and you need to know how to do calculus; or just look at the chart in Dan Poynter's book.


Experience is a difficult teacher, she gives you the test first and the lesson afterward

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2. People who jump from heights into pools, what are their speeds as they hit the water and how high are they jumping from? Are they reaching speed of 120mph?

Answer: Dana Kunze, Record High Dive holder at 172 feet, tumbling type feet first entry. http://www.youtube.com/watch?v=4uHkyMh9FW4

Still looking for his speed at entry.



From 172 feet he's falling about 60 mph.

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Let's not reply to this poster until he fills out his profile with a name and DZ where he jumps. All of his posts are asking basic questions that a real jumper might know, but some of the info is the type of stuff that would be of interest to a reporter or lawyer. Note that he signed up to DZ.com 9 years ago, but he's only asking very basic questions.

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In the 1st second you will fall about 16 feet. At the two second mark you will have fallen about 64 feet. At the three second mark you will have fallen about 144 feet. At the four second mark you will have fallen about 256 feet. At the five second mark you will have fallen about 400 feet.

I say "about" because I am not taking aerodynamic drag into account.



:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D

Well, we all know that terminal velocity has nothing to do with aerodynamic drag.
...

The only sure way to survive a canopy collision is not to have one.

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Davelepka,

I was hoping to ask some simple questions regarding Skydiving and want people to stay on topic without making False Accusations, Speculation and Comments that are Off Topic especially if it involves me, which it has. I'm not here to be your friend or to be popular. I don't need to know and have no desire to know who you are. I'm interested in asking some questions and learning something. My questions are on topic and relative to the forum.

Would you politely remove your off topic posts to my questions before I contact the website administrator and have them do it for you? If that is necessary, then you will be wasting their time and my time because of YOUR inappropriate public behavior.

If I wish to remain anonymous, guess what, it's NONE OF YOUR BUSINESS and it's probably a good idea. Ever hear of Identity Theft, Psychopaths, Sociopaths, Cyber Bullies, Mentally Ill Violent people who want to harm you etc? Guess what, they exist everywhere.

Your responses are Off Topic, Accusatory, Speculatory and you are saying this in a public forum. Amounts to inappropriate behavior.

If you feel the need to Speculate, Investigate, whatever...Use Private Messaging, your telephone and leave your responses out of my posts. I do not want you to post your responses to my questions if they are going to be off topic, accusatory and speculative

Quote


Let's not reply to this poster until he fills out his profile with a name and DZ where he jumps. All of his posts are asking basic questions that a real jumper might know, but some of the info is the type of stuff that would be of interest to a reporter or lawyer. Note that he signed up to DZ.com 9 years ago, but he's only asking very basic questions.

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1. Supposed you jumped off of a building, bridge, cliff, balloon...how many feet would you have to fall before you reach 120mph?

Answer: "A typical skydiver in a spread-eagle position will reach terminal velocity after about 12 seconds, during which time they will have fallen around 450 m (approx 1,500 ft)." Found here: http://en.wikipedia.org/wiki/Free_fall under Examples.


2. People who jump from heights into pools, what are their speeds as they hit the water and how high are they jumping from? Are they reaching speed of 120mph?

Answer: Dana Kunze, Record High Dive holder at 172 feet, tumbling type feet first entry. http://www.youtube.com/watch?v=4uHkyMh9FW4

Still looking for his speed at entry.



usually about 500
Look out for the freefly team, Smelly Peppers. Once we get a couple years more experience we will be a force to be reckoned with in the near future! BLUES!

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1. Supposed you jumped off of a building, bridge, cliff, balloon...how many feet would you have to fall before you reach 120mph?

Answer: "A typical skydiver in a spread-eagle position will reach terminal velocity after about 12 seconds, during which time they will have fallen around 450 m (approx 1,500 ft)." Found here: http://en.wikipedia.org/wiki/Free_fall under Examples.


2. People who jump from heights into pools, what are their speeds as they hit the water and how high are they jumping from? Are they reaching speed of 120mph?

Answer: Dana Kunze, Record High Dive holder at 172 feet, tumbling type feet first entry. http://www.youtube.com/watch?v=4uHkyMh9FW4

Still looking for his speed at entry.



usually about 500
Look out for the freefly team, Smelly Peppers. Once we get a couple years more experience we will be a force to be reckoned with in the near future! BLUES!

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Davelepka,

I was hoping to ask some simple questions regarding Skydiving and want people to stay on topic without making False Accusations, Speculation and Comments that are Off Topic especially if it involves me, which it has. I'm not here to be your friend or to be popular. I don't need to know and have no desire to know who you are. I'm interested in asking some questions and learning something. My questions are on topic and relative to the forum.

Would you politely remove your off topic posts to my questions before I contact the website administrator and have them do it for you? If that is necessary, then you will be wasting their time and my time because of YOUR inappropriate public behavior.

If I wish to remain anonymous, guess what, it's NONE OF YOUR BUSINESS and it's probably a good idea. Ever hear of Identity Theft, Psychopaths, Sociopaths, Cyber Bullies, Mentally Ill Violent people who want to harm you etc? Guess what, they exist everywhere.

Your responses are Off Topic, Accusatory, Speculatory and you are saying this in a public forum. Amounts to inappropriate behavior.

If you feel the need to Speculate, Investigate, whatever...Use Private Messaging, your telephone and leave your responses out of my posts. I do not want you to post your responses to my questions if they are going to be off topic, accusatory and speculative

Quote


Let's not reply to this poster until he fills out his profile with a name and DZ where he jumps. All of his posts are asking basic questions that a real jumper might know, but some of the info is the type of stuff that would be of interest to a reporter or lawyer. Note that he signed up to DZ.com 9 years ago, but he's only asking very basic questions.




You are funny as fuck. I hope someone somewhere likes you.

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If I wish to remain anonymous, guess what, it's NONE OF YOUR BUSINESS and it's probably a good idea. Ever hear of Identity Theft, Psychopaths, Sociopaths, Cyber Bullies, Mentally Ill Violent people who want to harm you etc? Guess what, they exist everywhere.

Your responses are Off Topic, Accusatory, Speculatory and you are saying this in a public forum. Amounts to inappropriate behavior.

If you feel the need to Speculate, Investigate, whatever...Use Private Messaging, your telephone and leave your responses out of my posts. I do not want you to post your responses to my questions if they are going to be off topic, accusatory and speculative



BWAHAHAHAHA.

How many times did you fail the bar exam?

BWAHAHAHAHAAA.

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If I wish to remain anonymous, guess what, it's NONE OF YOUR BUSINESS and it's probably a good idea. Ever hear of Identity Theft, Psychopaths, Sociopaths, Cyber Bullies, Mentally Ill Violent people who want to harm you etc? Guess what, they exist everywhere.

Your responses are Off Topic, Accusatory, Speculatory and you are saying this in a public forum. Amounts to inappropriate behavior.

If you feel the need to Speculate, Investigate, whatever...Use Private Messaging, your telephone and leave your responses out of my posts. I do not want you to post your responses to my questions if they are going to be off topic, accusatory and speculative



BWAHAHAHAHA.

How many times did you fail the bar exam?

BWAHAHAHAHAAA.



Careful Andy.... useage of that sort of chortling is apparently a bannable offense.

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