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Minimum necessary speed for card to be able destroy glass

  1. Feb 2, 2015 #1
    1. The problem statement, all variables and given/known data
    Hello, I am international student, so sorry for possible mistakes in English. For our science night I naively choosed project, where I will try to calculate minimal necessary speed for thrown card to destroy glass (probably wine glass). There are two videos for illustration.


    and


    My physics teacher said that it is great idea, but he does not know, how to calculate it. We were thinking about it and the most important factors will be probably:

    1. Speed of the card (changing variable and our goal for calculating minimal necessary)
    2. Weight of the card, area of edge of the card, strength of the card
    3. Strength of the glass

    At first I should calculate theoretically, how big speed is necessary for that, and then try if human is really able to make this speed with playing card Bicycle. Or I can try calculate it for credit card or any other stronger type of card.

    2. Relevant equations
    I absolutely do not know, where should I start. I was searching some help on google and than I got here on article discussing bullet going through heads. I found it similar to my topic.
    So my questions are:

    Where should I start my research or what terms I should look on?
    Is it possible to calculate it at all?
    I am sure that no one in history calculated possible destruction of cards. Could I inspire in boomerang and ninja stars experiments? Or in shooted bullet going through various stuff?

    3. The attempt at a solution


    We were thinking about it and the most important factors will be probably:

    1. Speed of the card (changing variable and our goal for calculating minimal necessary)
    2. Weight of the card, area of edge of the card, strength of the card
    3. Strength of the glass

    Similar technique to boomerang and ninja star throwing.
     
  2. jcsd
  3. Feb 2, 2015 #2
    Something to consider: what physical phenomena would account for the fact that increased speed of the card would lead to breaking the glass? Speed alone is not sufficient in explaining why something would break (plenty of things can move at high speeds but remain intact)
     
  4. Feb 2, 2015 #3
    But only speed is changing. Other things like strength of the glass, card and so on I can not change. I can just give higher speed to the card. Or am I wrong? By the way is it possible to calculate it?
     
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