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B Punching double pane window

  1. Mar 9, 2016 #1
    If someone was to punch a double pane window from inside how far could the glass fly outside.. this window is 5ft off ground and I found glass as far as 15 ft away is this possible with a bare hand?
  2. jcsd
  3. Mar 9, 2016 #2
    It's definitely possible. It's also possible for it to be accompanied by a lot of blood.
  4. Mar 9, 2016 #3


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    We can estimate the velocity with which fragments fly away from the window and the implied speed of the punch..

    Lets assume the hand causes fragments of glass to fly out horizontally. They immediately start to fall under the effect of gravity. The time taken to reach the ground is given by..

    t = SQRT(2h/g) where h is the starting height and g = acceleration due to gravity.

    The velocity v with which they travel horizontally is give by

    v = d/t

    where d is the horizontal distance.

    substitute for t to give

    v = d/(SQRT(2h/g))

    d = 15 feet
    h = 5 feet
    g = 32 feet/s2


    V = 15*SQRT(2*5/32)
    = 8.4 feet per second (just under 6mph)

    A professional boxer can punch at 25mph so I can easily see fragments of glass going a lot faster and further than 15 feet.
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