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G forces understanding

  1. Nov 6, 2003 #1
    Just had a couple of discussions with a pal of mine lately about g forces. i notived me laking there knowledge about how those forces act on moving bodies and how to calculate (better said estimate) what impacts this has.

    Mainly we try to figure out how a moving animal is unfluenced by g forces and how we can estimate what gf they have to sustain.

    If there is a nice page around that could help us to understant this better or any help from the peops here this would be nice.
  2. jcsd
  3. Nov 6, 2003 #2


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    Can't point you to a page, but I can give you a couple of google keywords, biomechanics and biophysics. Also check out square-cube law, one of the basic principles.
  4. Nov 6, 2003 #3
    thx... i'll try to see what i can find out with them.
  5. Nov 6, 2003 #4
    If the moving object or animal were on a frictionless plane and no other opposing forces - it will continue to move at a constant speed infinately, reguardless of g.

    G only pulls down and continues to pull the animal toward the ground, while the animal must oppose this force, as soon as it stops opposing this force, it will be pull to the ground and its foward momentum will be stopped by friction.

    Is this what you are asking??? Or are you wanting the actual mechanics of the animals body???

  6. Nov 7, 2003 #5
    Not really. We both tried to figure out what g forces an animal (of what size ever) has to deal with it it makes for an example a steep turn like this. If you do this in a plane you will encounter several g during this procedure.
    So for beeing able to make an estimation about this I need to understand the physics behind g forces first.
    It has to do with cirular motion and centripetal forces but I need a bit more understanding of this.
  7. Nov 7, 2003 #6
    Calculate centripetal acceleration for circular motion using a=v^2/r This acceleration will be what you call a 'g' force.

    Pilots and astronauts are spun round in centrifuge type contraptions to see how they cope with g forces. Mere mortals tend to pass out at 5-7 g, but with training, an inflating suit, and a good genetic mix to help you cope, 11 g or more is possible. The Airforce in many countries now check their candidates for genetic ability to cope with g forces before deciding wether to train them or not!

    By 'guestimating' the speed at which an animal runs and the radius of its turning circle, you can calculate its g force. :smile:
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