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# Struggling with the Maths in AS Physics... Help/Opinions?

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1. So I started self teaching my AS levels a few months ago. I'm starting them this September in college.
My A level choices are Physics, Chemistry, Biology and Psychology.

I am coping fine in all of them apart from Physics.

I can grasp the concepts easily but when it comes to applying the mathematics I struggle every single time. Even when I look at the answers I can't understand how they got that.

Here's an example...

u = 0ms^-1, s = -560m, a = -g = -9.81ms^-2, t=?
Need to find t, so use s = u x t + 1/2 x a x t^2. (I understand this)

Stages of working it out...

a) s = u x t + 1/2 x a x t^2

b) -560 = 0 + 1/2 x -9.81 x t^2 (I understand how they got this)

c) t = square root of 2 x (-560) / -9.81 = 10.7s (1.d.p) = 11s (to the nearest second)

I don't understand how they got from b to c.

I understand the concepts of AS physics, but this is the type of thing I'm struggling with.
It happens so often that I'm starting to doubt my choice of taking it.

A few questions -

- How do they get from b to c in the above example?

- Will I be taught the method of how to get from b to c (for example) in lessons, or is this something you should already know how to do before hand?

- If I'm struggling a lot with the maths side of AS Physics so early on, should I consider taking something else instead?

Sorry if I sound like I'm babbling, it's late and this has really frustrated me.
Any help would be greatly appreciated, thanks.
2. All the SUVAT jazz is on these:

http://steve4physics.blogspot.co.uk/
http://www.livemaths.co.uk/
http://www.mathsnetalevel.com/ - this is brilliant for mechanics, kinematics, dynamics etc
3. Personally I'd recommend that you drop psychology and take maths A level instead. That way you'll get to study relevant concepts in depth (trig, mech and calcus will be especially useful) so when they come up in physics you'll already understand them. In answer to your second question, you will be instructed on method but it's likely that not too much time will be spent on it.
4. I agree with Torpedo Fish, drop psychology and take mathematics to (at least) AS level - things such as logarithms and trigonometry, which will come up in physics, can be tricky to learn unless you've studied them in maths. Just out of interest, any ideas on what you want to read at university?
5. (Original post by Torpedo Fish)
Personally I'd recommend that you drop psychology and take maths A level instead. That way you'll get to study relevant concepts in depth (trig, mech and calcus will be especially useful) so when they come up in physics you'll already understand them. In answer to your second question, you will be instructed on method but it's likely that not too much time will be spent on it.
Yeah, the college I'm going to won't let me study Maths due to my GCSE grade. I got a C in it however I did have extenuating circumstances as I was in hospital at the time of sitting the last exam. Maths has never been my strongest point, however I was expected to get at least a B, if not an A, which I might have gotten if I wasn't in hospital. I've tried explaining to them and they were understanding, however they still were reluctant as they require at minimum of a B, but really want an A from GCSE maths.

I don't enjoy maths either, I feel like I really have to work in order to get things which other people will get straight away, therefore I do not think it is a wise decision to take maths at AS level, considering I need A's.

(Original post by SBarns)
I agree with Torpedo Fish, drop psychology and take mathematics to (at least) AS level - things such as logarithms and trigonometry, which will come up in physics, can be tricky to learn unless you've studied them in maths. Just out of interest, any ideas on what you want to read at university?
I want to study medicine, now before anyone lectures me on what I should be taking and what I should have gotten at GCSE. I am FULLY aware of the admissions process and entrance requirements for every single University. For that reason I am definitely taking Chemistry and Biology, which I would've taken them anyway because I enjoy them the most. I have already picked out the 4 universities I will be applying for, which were decided by looking at their teaching methods and their GCSE requirements, which I meet.

I'm not saying you were going to lecture me, but I've came across more than a few on here that think they know it all and will advise me wrongly, so I had to get that point across.
6. (Original post by lsaul95)
I want to study medicine, now before anyone lectures me on what I should be taking and what I should have gotten at GCSE. I am FULLY aware of the admissions process and entrance requirements for every single University. For that reason I am definitely taking Chemistry and Biology, which I would've taken them anyway because I enjoy them the most. I have already picked out the 4 universities I will be applying for, which were decided by looking at their teaching methods and their GCSE requirements, which I meet.

I'm not saying you were going to lecture me, but I've came across more than a few on here that think they know it all and will advise me wrongly, so I had to get that point across.
I'm not an expert on medicine admissions, but I always got the impression that chemistry and biology were the two important subjects for medicine, especially chemistry - in which case you would be right in the subjects that you are taking. Could you retake your maths GCSE perhaps? In any case, you could always drop physics after AS and continue on with Chemistry, Biology and Psychology - but you never really know until results day.
7. (Original post by lsaul95)
Here's an example...

u = 0ms^-1, s = -560m, a = -g = -9.81ms^-2, t=?
Need to find t, so use s = u x t + 1/2 x a x t^2. (I understand this)

Stages of working it out...

a) s = u x t + 1/2 x a x t^2

b) -560 = 0 + 1/2 x -9.81 x t^2 (I understand how they got this)

c) t = square root of 2 x (-560) / -9.81 = 10.7s (1.d.p) = 11s (to the nearest second)

I don't understand how they got from b to c.
I think putting in an extra stage will help;

a) s = u x t + 1/2 x a x t^2

b) -560 = 0 + 1/2 x -9.81 x t^2 (I understand how they got this)

c) -560/ (1/2 x -9.81) = t^2

//a fraction divided by another fraction can be flipped over and multipled if that makes sense***

d) (-560 x 2) / -9.81 = t^2

e) t = square root of 2 x (-560) / -9.81 = 10.7s (1.d.p) = 11s (to the nearest second)

*** e.g.

1/2 divided by 1/3 = 1/2 * 3/1

4/10 divided by 3/5 = 4/10 * 5/3

EDIT: in response to how you can help with your maths, I'd recommend sitting in on mechanics lessons being taught at your school.
8. (Original post by SBarns)
I'm not an expert on medicine admissions, but I always got the impression that chemistry and biology were the two important subjects for medicine, especially chemistry - in which case you would be right in the subjects that you are taking. Could you retake your maths GCSE perhaps? In any case, you could always drop physics after AS and continue on with Chemistry, Biology and Psychology - but you never really know until results day.
You are correct.
Yeah, I'm going to ask about resitting, however, that may make me worse off with some of the universities as some do not accept GCSE resits.
I was thinking about getting this - Calculations for Physics A level which might help me throughout.
9. (Original post by BigBear7)
I think putting in an extra stage will help;

a) s = u x t + 1/2 x a x t^2

b) -560 = 0 + 1/2 x -9.81 x t^2 (I understand how they got this)

c) -560/ (1/2 x -9.81) = t^2

//a fraction divided by another fraction can be flipped over and multipled if that makes sense***

d) (-560 x 2) / -9.81 = t^2

e) t = square root of 2 x (-560) / -9.81 = 10.7s (1.d.p) = 11s (to the nearest second)

*** e.g.

1/2 divided by 1/3 = 1/2 * 3/1

4/10 divided by 3/5 = 4/10 * 5/3

EDIT: in response to how you can help with your maths, I'd recommend sitting in on mechanics lessons being taught at your school.
I understand that a fraction divided by another fraction can be flipped over and multiplied, I can do that part, however I am still very much lost on re-arranging the equation properly, or even where I would begin to do that.

b) -560 = 0 + 1/2 x -9.81 x t^2 (I understand how they got this)
c) -560/ (1/2 x -9.81) = t^2

I don't understand how b) is re-arranged to make t the subject in c). BLAAAAH. It's probably something so simple. It's so frustrating.

Maybe Physics A level isn't for me, purely because of the maths.

EDIT: Maybe I have spotted it...
I remember something about when it 'swaps sides it swaps sign' or something. Is this what it is in the case of the * replacing the =, therefore changing to /?
If not... Ignore this :}

EDIT 2: I thought brackets were always done first? I'm probably incorrect in this case, but It's confusing me why you don't do the brackets first? It would make more sense for me to put the
brackets like this (-560 / 1/2) / -9.81 = t^2 as if I saw c) below, I would automatically do 1/2 x -9.81 first?
c) -560/ (1/2 x -9.81) = t^2
d) (-560 x 2) / -9.81 = t^2
10. (Original post by lsaul95)
You are correct.
Yeah, I'm going to ask about resitting, however, that may make me worse off with some of the universities as some do not accept GCSE resits.
I was thinking about getting this - Calculations for Physics A level which might help me throughout.
The only thing you can do is to ring or email some university medicine admission tutors and see what they say (if you haven't done so already) - they may make an exception if you explain your extenuating circumstances.
11. (Original post by lsaul95)
I understand that a fraction divided by another fraction can be flipped over and multiplied, I can do that part, however I am still very much lost on re-arranging the equation properly, or even where I would begin to do that.

b) -560 = 0 + 1/2 x -9.81 x t^2 (I understand how they got this)
c) -560/ (1/2 x -9.81) = t^2

I don't understand how b) is re-arranged to make t the subject in c). BLAAAAH. It's probably something so simple. It's so frustrating.

Maybe Physics A level isn't for me, purely because of the maths.

EDIT: Maybe I have spotted it...
I remember something about when it 'swaps sides it swaps sign' or something. Is this what it is in the case of the * replacing the =, therefore changing to /?
If not... Ignore this :}

EDIT 2: I thought brackets were always done first? I'm probably incorrect in this case, but It's confusing me why you don't do the brackets first? It would make more sense for me to put the
brackets like this (-560 / 1/2) / -9.81 = t^2 as if I saw c) below, I would automatically do 1/2 x -9.81 first?
c) -560/ (1/2 x -9.81) = t^2
d) (-560 x 2) / -9.81 = t^2
If you whack it into a calculator, you'll see both of these return the same answer; I just put the brackets in there so you can see it's divided by (1/2 x -9.81) rather than just the 1/2.

I just put in step d so you could see how the original steps were working.

If I change the steps a little it might make it a bit more obvious where I'm coming from;

c) -560 / 1/2 = t^2 * -9.81
d) -560*2 = t^2 * -9.81
e) -560*2/-9.81 = t^2
and then square root.
12. (Original post by BigBear7)
If you whack it into a calculator, you'll see both of these return the same answer; I just put the brackets in there so you can see it's divided by (1/2 x -9.81) rather than just the 1/2.

I just put in step d so you could see how the original steps were working.

If I change the steps a little it might make it a bit more obvious where I'm coming from;

c) -560 / 1/2 = t^2 * -9.81
d) -560*2 = t^2 * -9.81
e) -560*2/-9.81 = t^2
and then square root.
It's not sinking in. There are still aspects of it which make me look like this -
If it's divided by (1/2 x -9.81), why don't you do the brackets first? Which would end up being -560 / -9.31 = t^2
Nah, that just made it more confusing, I don't know why/how you put the -9.81 over there :')

Ahh, thanks, but I think it's safe to say I definitely shouldn't be taking Physics in September.
13. Perhaps just think of it algebraically, for instance a = bcd, therefore d = a/bc

Now substitute a = -560, b= 0.5, c = -9.81, d= t^2. To get t alone, you simply square root both sides of the equation.

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