Mechanics 1 Help?

Hi all I need help with the following mechanics question (from June 2012)

For the question you need (I presume) the graph:

sorry about the poor qual :rolleyes:

but the question is:

Calculate the distance between A and B at the instant when B starts to run. (5 Marks)

I worked out that A decelerates after 1.6 seconds from the previous question. Also the total distance ran by A (when he meets B) is 9.8 metres, whilst B has run (when he meets A) is 8 metres.

I don't know what to do now :/

Reply 1

TenOfThem

This is the relay race yes

From the time B starts to the time they meet

A has run 9.8 and B has run 8

They are in the same place when they meet

How far extra has A run

Reply 2

saberahmed786

Original post by TenOfThem

This is the relay race yes

From the time B starts to the time they meet

A has run 9.8 and B has run 8

They are in the same place when they meet

How far extra has A run

A has run an extra 1.8 metres

what can I do with this :/

Reply 3

TenOfThem

Original post by saberahmed786

A has run an extra 1.8 metres

what can I do with this :/

That is the answer

Think about the context of the question

Reply 4

saberahmed786

Original post by TenOfThem

That is the answer

Think about the context of the question

it's five marks, I got two marks for getting the distance ran when they met (this was done for my mocks)

and when I checked Mr. M's answers he says it's 12.6 metres o.O

so confused :/

Reply 5

TenOfThem

Original post by saberahmed786

it's five marks, I got two marks for getting the distance ran when they met (this was done for my mocks)

and when I checked Mr. M's answers he says it's 12.6 metres o.O

so confused :/

I need to remind myself of the full question

What year is it

Reply 6

Mr M

Study Forum Helper

Original post by saberahmed786

it's five marks, I got two marks for getting the distance ran when they met (this was done for my mocks)

and when I checked Mr. M's answers he says it's 12.6 metres o.O

so confused :/

I hear that Mr M is very good. You should trust him.

TenOfThem

...

http://www.thestudentroom.co.uk/announcement.php?f=38&a=1218

Reply 7

saberahmed786

Original post by TenOfThem

I need to remind myself of the full question

What year is it

It's june 2012 but it's not available for download yet (I got it from my mock exam)

I've uploaded a picture again:

Reply 8

TenOfThem

Original post by Mr M

I hear that Mr M is very good. You should trust him.

http://www.thestudentroom.co.uk/announcement.php?f=38&a=1218

In that case I cannot really be fussed to turn on the laptop to get it again

So I will leave it with you

Reply 9

Mr M

Study Forum Helper

A has run 19.6 metres and B has run 8 metres but you need to take account of the 1 metre distance between them at the end.

TSR doesn't want June 2012 papers to be discussed at the moment so I am closing the thread. Sorry!