Really hard physics ( for me anyway )

[crazy legs]

Please help with the following:

2 trains going in the same direction @ 30m/s with a 600m gap.
Train in front (T1) has 8 carriages and 200 people and the engine cannot be turned off.
There is 9km of track left, if the second train (T2) can connect with T1 it can remotely turn off engine. But must connect going same speed.

Specifications:
Each carriage = 5.8x10tothepowerof3 kg
Each engine = 1.4x10tothepowerof4 kg

Max. driving force = 6.3kN
Max. braking force = 6.okN
Max. velocity = 180km/hr
Engine max. load = 8 full carriages
carriage capacity = 80 people

Thank you very much.

[brachiopod]

......And the question?

If they are both travelling at 30 ms^-1, they will never connect.
What are they supposed to do?
Why are their respective masses relevant?
What have the number of passengers got to do with it?

Are we supposed to work out the ticket revenue or something?

[Loosehead]

Yes we are struggling here we need to know what you are asking.

The second train can catch up by going faster than 45m/s but then it won't be doing the same speed so like Brachiopod I'm not sure what you are asking and all the other info is irrelevant but perhaps catching up is not what you are asking.

More info please!

[brachiopod]

I've got it !!!

The answer is that the impulse imparted per fare-paying passenger is;

2.6 kNm �^-1

(2.6 kiloNewton metres per pound Sterling)


(This assumes that;

the acceleration due to gravity approximates to 10ms^-2;
each passenger is on a Super-Saver Apex Return;

and that;

no-one has flushed the toilet between Kettering and Market Harborough.)

[shammydodger]

Kettering! That's where I was going wrong! I was mixing my SI & imperial stations.

[adonia]

light doesn't bend at that sort of speed,plus the fact that flush is contained on new railed transport ,leads me to the conclusion!

Branson may have links on this post!

[adonia]

cor ,the Japs have got it sewn up

300 mph?

[gen2]

What? 300 mph? I always reckoned 30 m/s was about 60 knots.

[adonia]

new maglev

[brachiopod]

I though everyone would suffocate if the train went faster than 20mph?

[ugly_bob]

new maglev? was that what Hammond was driving?

[Gef]

crazy, we need more info here.

How many carriages does the second train have?
How many people are on board?
Are any of them pregnant?
Are any of them smokers?

What sort of dimwit are you?

[bernardo]

<FONT COLOR="#FF0000" FACE="Arial Black, Comic Sans MS, Arial">
<MARQUEE BEHAVIOR=ALTERNATE>You are a Booliak!</MARQUEE></FONT>

because you have not explained what the question is.

[bernardo]

Oh poo... that was supposed to be all colourful and fancy but it didn't work.

[crazy legs]

The second train is just an engine with an engineer.
The goal is to connect both trains and stop them before they run out of track.
You can connect them both at 30m/s If the 2nd train speeds up and then decelerates at the right time.

If you need more info just ask.Thanks.

[pagey]

The question is implied. The latter train needs sufficient accelerative power and braking power to catch up with the first, out-of-control, train before it reaches the end of the track.

We do need more info though, the engineers train - is it just one engine? how much do the passengers weigh?

The question needs to be broken down into two parts, the stopping distance required by T1 (before reaching the end of the track) after its engine has been turned off (and brakes applied, I assume), given its total weight, braking power and velocity.

Subtract this stopping distance from the 9km you have, and this is the amount of distance (and hence time) T2 has to speed up and slow down to catch T1.

Its best to start with a visualisation - a time vs velocity graph, where distance can be calculated by area under the graph.

[crazy legs]

Engineers train is just one engine( no carriages ).
80kg per person (including luggage).