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I Force exerted by jumping dog

  1. May 20, 2017 #1
    Hey guys,

    I designed a ramp to go from a boat dock into the water, allowing our dog to exit the water. I've done some rough calculations to estimate how large of a buoy I need underneath my ramp, and am missing only one variable at this point. I have accounted for the "live weight" which includes our dog on the ramp. I know exactly how much our dog weighs, but am curious what sort of maximum load the ramp might experience considering our dog would be moving and accelerating the ramp as he climbs out. So I have two questions:

    1) What is a reasonable estimate for the maximum load my dog would place on the ramp while climbing out in terms of his weight. For example, 1.5 times his weight, 2 times his weight, etc.
    2) My second question is essentially the same as the first, except I am looking for an approximate physics explanation of how I could reasonably estimate this force. I assume this activity would be hard to pin down exactly and how be extremely dynamic, but a first order approximation is fine!

    Thanks for any help!
  2. jcsd
  3. May 20, 2017 #2


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    Care to share ? Preferably with a drawing/sketch/picture of the situation Helps helpers help you better ...
  4. May 20, 2017 #3
    No problem! I attached a picture. Please note that the sketches are not scale.... F_b refers to the buoyancy force generated from the submerged portion of the wood, which is approximately 15.28 lbs for my design. For simplicity in my question, lets assume that the ramp is rigid and will not move in response to the dog's movement. Basically, I will use the estimated "maximum load of the dog" to add to the ramp weight which will be my "F_w" variable. From here I can calculate the size of buoy needed to support the loaded ramp.

    Hope this helps and let me know if you have any other questions!

    Attached Files:

  5. May 20, 2017 #4


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    If a very athletic dog could exert a force 2x his weight, wouldn't he have accelerated 1G. Quite a high-jump. I would guess around 1/5 to 1/10 his weight.
  6. May 22, 2017 #5
    Thanks for the replies so far! Any additional input is appreciated!

  7. May 22, 2017 #6
    Can you time your dog climbing a stair? From a standstill how fast does he accelerate up ~3 steps. From and his weight you should be all set.
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