(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

[PLAIN]http://img443.imageshack.us/img443/3598/physicsproblem.png [Broken]

2. Relevant equations

Ok so I am first of I don't know when they said layer if they meant the number of people or the thickness? of the people I don't understand the question

3. The attempt at a solution

what I noticed is that at first the first guy will have to cross L distance but the second guy must cross (L-d) but then it get so complicated I mean how can I solve this? what I noticed is that for all 1 seconds they cross L distances so at the first 1/2 second the first guy will be at the door but then the second guy will be at his place but he will have to cross 1.5 m not 1.75 which will take him .42 seconds but that wont matter for the ones before him right? they will still have to cross .5 seconds to reach the before last place pfff it's too complicated to me that I can't even describe it rather than solve it

ok so what I can make out is that they move L distance for all .5 seconds

and if I call the door is where x = 0 and the left side is positive

then when they reach x=L they must cross (L-nd) distance while the first guy is where n = 0 .but that is not useful at all at finding how the layers increases.... but I tried lol

EDIT: I know this is stupid but is the book assuming the people are transperant because it would be easier if they can go through each other

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# Homework Help: 1 dimensional motion escape from a locked door

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