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Reply #18: It's all in the details, unfortunately [View All]

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BrewerJohn Donating Member (499 posts) Send PM | Profile | Ignore Mon Nov-24-03 10:13 PM
Response to Original message
18. It's all in the details, unfortunately
Force is the rate of change of momentum (of the impacting animal), so the force vs. time curve during the collision depends on the details of the collision, which are probably unpredictable. You can estimate an average force over the collision time, though, by estimating the total time the animal is in contact with you, and knowing whether it bounces off (and how fast) or just falls at your feet.

For example, if it hits you and then falls flat, the total momentum change is about (54.5 kg) X (26.8 meters/sec) (those being the metric equivalents of 120 pounds and 60 mph) = 1461 kg-m/s. If this happens over 0.1 second the average force is (1461 kg-m/s)/(0.1 s) = 14,610 kg-m/s^2 (or newtons), which converts to around 3285 pounds of force.
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  -a science question mmm  Nov-24-03 09:41 PM   #0 
  - What is the size of the impact zone?  ProudGerman   Nov-24-03 09:44 PM   #1 
  - f=ma  Zorba607   Nov-24-03 09:46 PM   #2 
  - you are being silly  mmm   Nov-24-03 09:52 PM   #3 
     - What's not simple about that?  HereSince1628   Nov-24-03 09:57 PM   #5 
     - No such thing  Kitsune   Nov-24-03 09:57 PM   #6 
     - it is simple  WannaJumpMyScooter   Nov-24-03 10:03 PM   #11 
        - Where are your units????  Catshrink   Nov-24-03 10:06 PM   #13 
        - Juice Newtons? I always loved her.  WannaJumpMyScooter   Nov-24-03 10:09 PM   #16 
        - except that you don't  forgethell   Nov-24-03 10:12 PM   #17 
           - oops. I missed that... that does make it a bit sticky  WannaJumpMyScooter   Nov-24-03 10:15 PM   #19 
  - what 120lb animal moves at 60mph?  WannaJumpMyScooter   Nov-24-03 09:55 PM   #4 
  - A Deer standing in the road in front of your speeding Subaru...  BiggJawn   Nov-24-03 09:58 PM   #8 
  - I hit a deer at 60  woofless   Nov-24-03 10:04 PM   #12 
  - thank you Big Jawn  mmm   Nov-24-03 10:07 PM   #15 
  - Golden retriever jumping from oncoming pickup truck  HereSince1628   Nov-24-03 10:01 PM   #10 
  - what size is "me?"  NaMeaHou   Nov-24-03 09:58 PM   #7 
  - Ok, let me ask you a few questions first.  kixot   Nov-24-03 10:00 PM   #9 
  - From an engineer...  GreenCommie   Nov-24-03 10:07 PM   #14 
  - Wayyyyyyyy overcomplicated.  kixot   Nov-24-03 10:17 PM   #20 
     - Yeah, it proabably is  GreenCommie   Nov-24-03 10:25 PM   #25 
        - if acceleration is assumed constant  Endangered Specie   Nov-24-03 10:28 PM   #27 
           - True...  GreenCommie   Nov-24-03 10:35 PM   #31 
  - It's all in the details, unfortunately  BrewerJohn   Nov-24-03 10:13 PM   #18 
  - hey, Oppenheimer, stick to the details given.  kixot   Nov-24-03 10:20 PM   #22 
  - What?  Waistdeep   Nov-24-03 10:23 PM   #24 
  - Re:  Endangered Specie   Nov-24-03 10:26 PM   #26 
  - The velocity of the animal changes....  GreenCommie   Nov-24-03 10:30 PM   #29 
  - acceleration due to gravity is inherent in the unit of weight given,.  kixot   Nov-24-03 10:38 PM   #34 
  - You better have taught it.  kixot   Nov-24-03 10:36 PM   #32 
  - Uh, I don't think so  BrewerJohn   Nov-24-03 10:42 PM   #37 
  - Even so 0.1 sec is too much time  Waistdeep   Nov-24-03 10:20 PM   #23 
  - ok, I thought about it and you're right with the point you make.  kixot   Nov-24-03 11:06 PM   #39 
  - youve got it dead wrong people!  Endangered Specie   Nov-24-03 10:19 PM   #21 
     - Yes it can be answered with the information given.  kixot   Nov-24-03 10:29 PM   #28 
        - ok, then answer it  Endangered Specie   Nov-24-03 10:34 PM   #30 
           - I did, above...  WannaJumpMyScooter   Nov-24-03 10:37 PM   #33 
           - I REPEAT:  Endangered Specie   Nov-24-03 10:39 PM   #35 
           - I know the perpendicular application of the weight nulls it in the sum  kixot   Nov-24-03 10:41 PM   #36 
              - Keep in mind  Endangered Specie   Nov-24-03 10:44 PM   #38 
                 - Hello, we ARE on Earth, no?  WannaJumpMyScooter   Nov-24-03 11:06 PM   #40 

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