Solving 1D Motion Problems with Fun: Average Rate and Time Calculations

[frasifrasi]

FUN 1d motion prob--help

Homework Statement

The figure (http://img471.imageshack.us/my.php?image=picprobfd5.png) shows a general situation where a stream of people attempt to escape through a door that is closed. The people move toward the door at a speed of v = 3.50 m/s, are each d = .25 m in depth, and are separated by L = 1.75m. The arrangement in the figure occurs at t = 0. a.) at what average rate does the layer of people at the door increase? b.) at what time does the layer's depth reach 5 m ?

Homework Equations

The picture I drew is exactly like the one in the book.

The Attempt at a Solution

I relly have no idea how to start, but it is the 1d motion section of fundamentals of p.

Thank you.

 

[frasifrasi]

Pleaseeeee

 

[learningphysics]

How long does it take for the guy closest to the door to get to the door... The length of the layer increases from 0 to 0.25m, in this amount of time...

 

[frasifrasi]

learningphysics, all the info is there--I copied it exaclty. I really need help getting started.

 

[learningphysics]

learningphysics, all the info is there--I copied it exaclty. I really need help getting started.

I know... I'm trying to guide you along.

How long does it take the guy closest to the door to get to the door? Calculate this time... Look at the picture... what is the distance to the door? How fast is he walking? You have everything you need to get the time it takes...