When a high-speed train traveling at 125 km/h rounds a bend, he sees a locomotive 642 m ahead. The locomotive is moving at 24 km/h.?

A toy train consisting of a locomotive and four carriages. The couplings between the carriages are magnetic.
A child pulls the train (locomotive) with a force of 2 N. Each car has mass 50g and the locomotive has mass 200g

A) What is the train's acceleration in m / s ^ 2?
B) What is the force in the coupling between the locomotive and the first car?
C) What is the force in the coupling between the first and second cart?
D) If the child pulls the train with force F, then the train to go apart. In what connection?

My solution:

a) F = m * a => F / m = a 2 / (0.05 * 4 + 0.2) = 5m / s ^ 2
ANSWER: 5m / s ^ 2
b) F = m * a 0.2 * 5 = 1 N
ANSWER: 1 N
c) F = m * a (3 * 0.05) * 5 = 0.75N
ANSWER: 0.75 N
d) ANSWER: The coupling between the locomotive and first carriage.

All answers are correct, but need to motivate subquery D. Why is it just the coupling between the locomotive and the first car?

I'm not sure where Mr 357 is getting his info about them not doing anything useful. They are the most cost effective way we have to haul freight. If it wasn't for trains the highways would be so clogged with trucks you couldn't move. One 8,000 foot double stack train can haul the equivalent of 300 trucks. If it wasn't for trains just about everything you buy would be much more expensive to buy. They are so much more fuel efficient than trucks there is no comparison with the cost of diesel being so high these days. People just hate waiting for them to clear crossings because everyone is in such a hurry these days.

Source:

UPRR engineer

Asker's rating & comment

I just moved to Beaver County in Pennsylvania and I'm looking for cool places to visit. Museums, train/rail rides, parks near river, ect?

You can buy a ticket at the station - and cash is fine.

Railway stations have signs and indicators all over the place - and staff who will explain things if you can't work out where to go. If in doubt - ask someone in a staff uniform.

Yes you can pay cash, all main railway stations should be able to sell you the tickets.
If you are under 18 they might want to see proof of your parents permission and if you seem to be under 18 they might want to see your ID (or passport/driving license) to proof your age.

Before you go to Brussels, you can get a print out of the travel, which will have all the times and maybe even details like the track where the train leaves.
When you go to the station you will see big boards with all the trains leaving the next hour or so, you need the Grande Lignes.(spelling?) the main lines.
The Thalys trains leave from the same part of the station, often the same track even but there are a few different ones they share.

You always have to bring your passport of European ID, when you pass a border, so when going to Brussels you need to do it as well.
When you get to the thalys you will find staff at every door, they check your ticket and send you on when you are at the wrong door.
In Brussels there is only one stop, so that is where you go out.

They will announce the stop, but you can also see on your time sheet that you are near.

Thalys trains usually run on time, but they can be a bit late some of the time. When I used them never more than a few minutes.