# A level Maths Mechanics help

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Please can someone help!!!!

I’ve tried really hard to do Question 3 by myself but I can’t work out how to do it. Any help would be so appreciated xxx

I’ve tried really hard to do Question 3 by myself but I can’t work out how to do it. Any help would be so appreciated xxx

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#2

(Original post by

Please can someone help!!!!

I’ve tried really hard to do Question 3 by myself but I can’t work out how to do it. Any help would be so appreciated xxx

**littlebitthick**)Please can someone help!!!!

I’ve tried really hard to do Question 3 by myself but I can’t work out how to do it. Any help would be so appreciated xxx

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(Original post by

First you need to find the resultant force on the particle. Any ideas?

**Notnek**)First you need to find the resultant force on the particle. Any ideas?

Then using Pythagoras get the square root on 37

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#4

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So add the vectors together to get 6i -j

Then using Pythagoras get the square root on 37

**littlebitthick**)So add the vectors together to get 6i -j

Then using Pythagoras get the square root on 37

**F**= m

**a**to find the acceleration vector. The question doesn't ask for the magnitude of the acceleration but it isn't completely clear.

Once you have the acceleration as a vector you can use SUVAT with vectors to find the initial velocity vector

**u.**

Try this and post your working if you get stuck.

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(Original post by

Well you could leave it as a vector and then use

Once you have the acceleration as a vector you can use SUVAT with vectors to find the initial velcocity vector

Try this and post your working if you get stuck.

**Notnek**)Well you could leave it as a vector and then use

**F**= m**a**to find the acceleration vector. The question doesn't ask for the magnitude of the acceleration but it isn't completely clear.Once you have the acceleration as a vector you can use SUVAT with vectors to find the initial velcocity vector

**u.**Try this and post your working if you get stuck.

Then my initial velocity becomes negative and that confuses me.

Does that just mean that the initial velocity of the particle is the opposite direction to that of the acceleration??

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#6

(Original post by

My problem is that if I use a= square root of 37

Then my initial velocity becomes negative and that confuses me.

Does that just mean that the initial velocity of the particle is the opposite direction to that of the acceleration??

**littlebitthick**)My problem is that if I use a= square root of 37

Then my initial velocity becomes negative and that confuses me.

Does that just mean that the initial velocity of the particle is the opposite direction to that of the acceleration??

**v**=

**u**+

**a**t where

**v**is the vector 0

**i**+ 0

**j**.

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Oh okay. I’ve never done it like that before. So by Putting the vector 6i-j into F=ma when the particle is 2kg, you would just end up with 3i -1/2 j as ur acceleration vector??

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#8

(Original post by

Oh okay. I’ve never done it like that before. So by Putting the vector 6i-j into F=ma when the particle is 2kg, you would just end up with 3i -1/2 j as ur acceleration vector??

**littlebitthick**)Oh okay. I’ve never done it like that before. So by Putting the vector 6i-j into F=ma when the particle is 2kg, you would just end up with 3i -1/2 j as ur acceleration vector??

A question may ask for e.g. the magnitude of the velocity (i.e. the speed) but if not just leave answers as vectors.

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