You are Here: Home >< Maths

# Mechanics 1- Connected Particles

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016

1. A train consists of an engine of mass 50,000kg coupled to two trucks A and B of masses 10,000kg and 6,000kg. The train moves along the track horizontally at constant deceleration. The tension in the coupling between truck A and truck B is zero.

i) By applying newtons second law to truck B, show that the deceleration is 0.25ms^-2

ii) Find the tension in the coupling between the engine and A

iii) Determine whether the engine exerts a driving force or a braking force and find its magnitude.

No idea how to go about this, any ideas on a method to work this out, all questions on my assignment are simular to this one.
2. F=ma
the mass is 6000 and the force is -1500
rearrange to find the deceleration

Can't remember how to do ii or iii atm, I'll edit this if I remember
3. If this is a university assignment, we can't really help you.

Mark T the tension in the towbar between the engine and A. It points both ways into the centre of the towbar.

Mark X the driving force at the front of the engine (remember it could be a braking force but it will just come out with a negative magnitude if this is the case).

Apply F = ma on whatever sections you like.
4. (Original post by Mr M)
If this is a university assignment, we can't really help you.

Mark T the tension in the towbar between the engine and A. It points both ways into the centre of the twobar.

Mark X the driving force at the front of the engine (remember it could be a braking force but it will just come out with a negative magnitude if this is the case).

Apply F = ma on whatever sections you like.
Not a university assignment! It's M1 as level, okay I'll try your method be back in 10
5. (Original post by Mr M)
If this is a university assignment, we can't really help you.

Mark T the tension in the towbar between the engine and A. It points both ways into the centre of the towbar.

Mark X the driving force at the front of the engine (remember it could be a braking force but it will just come out with a negative magnitude if this is the case).

Apply F = ma on whatever sections you like.
I get a positive tension and a negative X for this question.

I took X in the right direction, but due to the negative answer it is acting at left, so its a braking force. But why is the tension positive, shouldn't it be negative, because won't the braking force cause thrust?
6. (Original post by raheem94)
I get a positive tension and a negative X for this question.

I took X in the right direction, but due to the negative answer it is acting at left, so its a braking force. But why is the tension positive, shouldn't it be negative, because won't the braking force cause thrust?
I think you can answer the question yourself by looking at the system as a whole or, if you have already done that, look at the forces on the engine. You will find the equations are not consistent.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
your full birthday is required
1. Oops, you need to agree to our Ts&Cs to register

Updated: April 15, 2012
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

Poll
Useful resources

## Make your revision easier

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams

Can you help? Study help unanswered threads

## Groups associated with this forum:

View associated groups
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.