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Greychu
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An abrupt slowdown in concentrated traffic can be travel as a pulse, termed a shock wave, along the line of cars, either downstream (in the traffic direction) or upstream, or it can be stationary. Figure below shows a uniform spaced line of car moving at speed v = 25.0 m/s toward a uniformly spaced line of slow cars moving at speed vs = 5 m/s. Assume that each faster car adds length L = 12.0 m (car plus buffer zone) to the line of slow car when it joins the line, and assume it slows abruptly at the last instant.
(a) For what separation distance d between the faster cars does the shock wave remain stationary?
If the separation is twice that amount, what are the
(b) Speed and
(c) Direction (upstream or downstream) of the shock wave?
For clearer detail, take a look on the attach files.
My works:
(a)
15 = [tex]\frac{d+nL}{\Delta t}[/tex] ... (1)
(average speed of the faster car before and after it join the line.
5 = [tex]\frac{nL}{\Delta t}[/tex] ... (2)
Suppose that at time = [tex]\Delta t[/tex], the faster car (closest to the slower car line) joins the slower car line, and it's speed decrease to 5 m/s.
(2) - (1) yields 10 = [tex]\frac{d}{\Delta t}[/tex]
The problem is I can't find a value of [tex]\Delta t[/tex], making the part (a) cannot be solved...
I need to know how to do part (a) so that I can do part (b) and (c) as well.
http://www.amasci.com/amateur/traffic/traffic1.html for more detail about traffic shock wave.
(a) For what separation distance d between the faster cars does the shock wave remain stationary?
If the separation is twice that amount, what are the
(b) Speed and
(c) Direction (upstream or downstream) of the shock wave?
For clearer detail, take a look on the attach files.
My works:
(a)
15 = [tex]\frac{d+nL}{\Delta t}[/tex] ... (1)
(average speed of the faster car before and after it join the line.
5 = [tex]\frac{nL}{\Delta t}[/tex] ... (2)
Suppose that at time = [tex]\Delta t[/tex], the faster car (closest to the slower car line) joins the slower car line, and it's speed decrease to 5 m/s.
(2) - (1) yields 10 = [tex]\frac{d}{\Delta t}[/tex]
The problem is I can't find a value of [tex]\Delta t[/tex], making the part (a) cannot be solved...
I need to know how to do part (a) so that I can do part (b) and (c) as well.
http://www.amasci.com/amateur/traffic/traffic1.html for more detail about traffic shock wave.
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