Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Throwing a pebble

  1. Feb 12, 2007 #1
    Throwing a pebble :)

    How far (and fast) can a 1.8 m tall, 80 kg heavy (average male) person throw a pebble that's, say, 3 cm in diameter (without any help - just a man (his clothes included :) ) and a pebble - nothing more)?

    It's a very interesting issue - think about it, it motivates. I mean - it's a kind of 'super-power' - as close as it gets. For example: imagine that you're left in a forest (no civilization in sight) you want to hunt something to eat but you have NOTHING on you that can serve you to accomplish such task; but you were training pebble-throwing all your life, and you are extremely precise and can deliver a lot of force (a wunderkind for it if you will). Man - it's THE simplest weapon - it cannot get any simpler than that! It's fascinating stuff - it's a genuine power for ya! You have your body, and pebbles are practically everywhere; people would be stunned seeing that you have a skill to turn that little elements (I mean - the basic ones!) into something that admirable. There's no other word for it - it's just - pure amazing...
    So I, basically, in fact ask if it is possible at all.

    I mean - never mind - take ANY approach you want... (the result is what's important here)
    ...Let's say: for testing purposes you have an adjustable machine/apparature that can fire pebbles and give you data on stuff about it; and you have a wild-bore or a deer 100m from it, so, first - how strong it must "fire a pebble" in order for it to hit that animal in a head (I mean - anywhere where it would be the most efficient) and incapacitate it?
    Only then - how strong and agile must a person be to fire a pebble with such force and speed (I mean - it's not sharp, so pure force is of the essence here)?
    (of course you don't have to stand still while throwing it; you can do anything you want - any technique - just to launch that pebble from your mere hand and it flies like a bullet)

    I'm talking ballistic pebbles here. :)
  2. jcsd
  3. Feb 12, 2007 #2


    User Avatar
    Staff Emeritus
    Science Advisor

    You need to work out how much force a man can apply to the object before he releases it. This will determine how fast it will be travelling just after he releases it, and how far he will be able to throw it.

    I don't know whether you're looking for an answer here. I have no idea what the maximum velocity a man can throw a pebble with is!
  4. Feb 12, 2007 #3
    If you dig through www.dstan.gov.uk[/URL] there is a standard for the human factors design of equipment which has all sorts of data about the capabilities of Men and Women covering 5th to 95th percentile human.

    I would recomend it as not only a good cure for insomnia, but essential reading for people who design things that somebody else has to maintain.
    How many times have you need to reach a nut 3 feet down a hole you can't get your hand through.
    Last edited by a moderator: Apr 22, 2017
  5. Feb 12, 2007 #4


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    This is not a physics problem. Moving to GD, and reporting, so perhaps the mentors can confab and figure out where it belongs.
  6. Feb 18, 2007 #5
    Quote: "This is not a physics problem."

    Length of arm, acceleration of objects, force, mass, velocity, properties of materials... it seems 'physics'...

    (the main question was: What speed pebble must travel at to do the job, and what (I guess unrealistic) physical properties of a human would allow those results?)
    Last edited: Feb 18, 2007
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook