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  1. #14
    Join Date
    Nov 2003
    Location
    Boston
    Posts
    600
    How tall was he?

  2. #15
    Join Date
    Aug 2003
    Posts
    1,841
    Did he have parashot pants on?

  3. #16
    Join Date
    Aug 2001
    Location
    Eastern Washington
    Posts
    2,990
    I fell off a 24' extension ladder once, landed on my feet kind of off balance, hit the ground and rolled arround a bit, didn't get hurt though. Good thing I was only on the bottom rung.
    TB
    Everyone knows something I don't.

    2 Chronicles 7:14
    14 if my people, who are called by my name, will humble themselves and pray and seek my face and turn from their wicked ways, then will I hear from heaven and will forgive their sin and will heal their land.

  4. #17
    Join Date
    Aug 2001
    Location
    Eastern Washington
    Posts
    2,990
    Originally posted by TB
    Originally posted by reverunbilly
    a 230lb. man fell 8 ft. from a step ladder. his safety belt caught him at 1 ft. from the floor. how much psi was put on the safety harness?
    OK, I'll take a stab at it.

    An object from rest accelerates in free fall at 32 ft./sec/sec. At 8 ft, he would be travelling 4 ft/sec

    E=MC^2

    230 lbs x 4 ft/sec^2 =

    (230)(16)=

    3680 ft. lbs. of force
    Shoot! I did it wrong

    At 8' he would be travelling 8 ft./sec (32ft/sec/sec x .25sec)

    (230)(8^2)=

    (230)(64)=

    14,720 ft lbs

    Now of course that assumes two things; 1) that "psi" is not actually what was wanted, wrather "energy" was, and 2) that he fell 8' from the top of the ladder down toward the floor, of course falling "...8' from a step ladder..." could also mean he fell before walking to within 8' of where the ladder stood.

    Just funnin with ya, but I had fun with the math
    TB
    Everyone knows something I don't.

    2 Chronicles 7:14
    14 if my people, who are called by my name, will humble themselves and pray and seek my face and turn from their wicked ways, then will I hear from heaven and will forgive their sin and will heal their land.

  5. #18
    Join Date
    Dec 2004
    Location
    newton,mass.
    Posts
    6,109
    Originally posted by TB
    I fell off a 24' extension ladder once, landed on my feet kind of off balance, hit the ground and rolled arround a bit, didn't get hurt though. Good thing I was only on the bottom rung.
    TB; thats to funny, but in all seriousness you had your boots on the wrong feet again didn't you. (and not someone else's feet either ). Maybe try a smaller ladder when your getting the cheerios from above the kitchen counter, just a thought.
    "Nothing else can poison our culture, corrupt our society or ruin the character of our people like unearned money or unearned opportunity." -- James R. Cook

    "Fooling around with alternating current is just a waste of time. Nobody will use it, ever." Thomas Edison, 1889.

  6. #19
    the 230lb man actually only fell 7ft. so at 32 ft per sec. the psi on the safety harness would be ?

  7. #20
    Join Date
    Jan 2003
    Location
    San Jose, Ca
    Posts
    2,089
    Originally posted by reverunbilly
    a 230lb. man fell 8 ft. from a step ladder. his safety belt caught him at 1 ft. from the floor. how much psi was put on the safety harness?
    Digging through the opd physics books here (tried the brain but came up empty) I find we are missing some facts.

    What kind of line was he tied to , rope, chain, or spriing stop. we can calulate (I did not say I did I just said we could) any way we can calulate his speed as he begasin to stop. If we could calculate the time it took for him to stop assuming constant deacceleration we can calculate the force required to stop him.

    To calulatte the pressure required to stop him we would also need the area that the force is spread over (PSI).

    We can calculate the energy required to stop him. And we could calculate his momentum if we wanted to.

    What are we doing here I graduated years ago, All we really needd to know is that it is not that hurts, but the landing.
    Old snipes don't die they just loose their steam

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