Toby W

I'm not bothered about getting 60fps at 1080p on ultra settings.

Do you think these specs will be able to get around 45fps at 720p on mid-high settings for 'new' (lets say battlefield 4) games?

Operating System: Windows 8 64-Bit

Graphics: NVIDIA GeForce GTX 765M 2GB GDDR5

Storage: Western Digital Black 750GB 7200RPM Boot/Storage Drive

intel® Core™ i5 4200M 2.50GHz Processor (3.10GHz Turbo)

Memory: 4GB DDR3 System Memory at 1600MHz (2GB x 2) (Will upgrade this to 8GB)

I've seen many different names for the CONH group, I get that it's the secondary amide group but in my textbook I've also seen it referred to by other names.

It's not directly stated, but from my interpretation...

In the Context of Polyamides, the CONH group is referred to as 'amide link'

in the Context of Proteins, the CONH is referred to as a 'peptide linkage'

Can anyone confirm or correct this?

It's been a while since I've done any redox reactions questions and this one has stumped me completely.

The questions here, it's a little wordy so I thought It would be best to upload it as an image http://oi39.tinypic.com/2i0zw2f.jpg

Thanks for your help!

I was given two questions, the first to draw the Structure of 2-bromobutane, and the second to use three-dimensional diagrams to draw one of the possible structures of the two optical isomers of the compound.

Here are my answers: http://tinypic.com/r/2zdyh5x/5

The first part was fine, and I got it right.

My teacher marked the second part wrong however, crossing out the Br and H groups and swapping their positions. I'm not however sure why I got it wrong (basing the 3D-representation off of the first structural formula) and I would like to know how, in the future, I can insure that I place the right groups in the right positions.

I'm having a few problems with Animal Crossing: New Leaf.

First of all, I've never had the ability to buy red turnips from Joan. I hear if you time travel, the ability is locked for the week, but I've never done that. Also, I haven't even had the ability to ask about purchasing them, nor in any of her dialogue does she mention them, as if they've been removed from the game.

Similarly, despite 'unlocking' the ability well over a week ago, whenever I ask for work from Brewster he always "Doesn't need any help". Common explanations as to why this happen are

-An event is happening (ie bug off)

-A special character is visiting (ie CrazyRedd)

-You have to do it between 11am-11pm

-You don't have 2 empty slots in your inventory.

I have tried at multiple times of the day to ask for help, on multiple days when none of the above criteria are applicable, but I never get anywhere.

Does anyone know what's up? It's starting to get pretty annoying...

I always assumed the mod command simply gave the remainder of a division

ie 7 mod 3 = 1 and

15 mod 3 = 2

But my computing teacher said it can only return the value 1 or 0, depending or wether or not there IS a remainder

ie 15 mod 3 = 1 (because there is a remainder)

100 mod 10 = 0 (because there isn't)

I've got this questions

01101101

00100111

00101101

_________

Now, I was only taught how to add 2 binary numbers together, and so I know for rules that

1 + 0 = 1,

0 + 1 = 1,

0 + 0 = 0

1 + 1 = 0 (carry 1)

and 1 + 1 + 1 = 1 (carry 1)

However, with this question there is the possibility of

1 + 1 + 1 + 1 of which I have no clue what to do, so if any help of how to do these questions (Without adding the first 2 binary numbers together initially and then adding the result to the final one- I can do that but the amount of space I've been given suggest it's not what the examiners are looking for)

The stem and leaf diagram illustrates the heights in metres of 25 young oak trees

3| 4 6 7 8 9 9

4| 0 2 2 3 4 6 8 9

5| 0 1 3 5 8

6| 2 4 5

7| 4 6

8| 1

key: 4|2 represents 4.2

The question is "Use your calculator to find the mean and standard deviation of this data"

It's an exam question BUT it's only worth 3 marks- so you're expected to be able to do it in 3 minutes

The only way I've been taught how to do this type of question is

(for the mean) to add each number individually (3.4+3.6+3.7.... ect) then divide by 25. That in itself would take more than 3 minutes, not to mention then going on to work out Sxx (3.5- mean)^2 + (3.6 - mean)^2...

Infact, in class when I tried this question, it took me 50 minutes. Keep in mind the test paper it's taken from is only 1 hour 30 minutes, and it's only worth 3 marks (Next question used the answers from this one... but still that's 7 out of 72 marks taking up well over half the allotted time) there must be a quicker way of working it out, right? If not, I'm avoiding any similar question to this like the plague.

A level exams and rounding values?

As a rule of thumb, unless specified specifically by the question, when working out long calculations in physics or maths I will always use exact values (ie to answer a question takes multiple 'steps' I won't round my answer for step one when using it in step 2) and then only round my final answer (usually to 3.sf, unless the question asks for it to a different degree of accuracy)

I've noticed recently however in mark scheme's, it is often the case that values are rounded at the end of every 'step', despite recalling from my teacher that you should never do this. As a result, final answers can often be different by a significant amount, even though the method used is identical. Just wondering if the way I approach questions at the moment will give me maximum marks, or if I should quickly adopt the 'mark scheme method' of rounding everything as I get them.

For example, in one physics question...

An object of mass 1500kg is lifted 25 metres at a speed of 1.6ms-1

i) work out the time taken

MY WORKING

25/1.6 = 15.625 = 15.6 seconds

MARK SCHEME

25/1.6 = 15.625 = 15.6 seconds (So far so good..)

ii) work out the tension in the string lifting the object.

MY WORKING

Since the object is at a constant velocity, net force must be 0. Therefore tension = weight

1500 x 9.81 = 14715N

MARKSCHEME

1500 x 9.81 = 14700 (This is where it starts to go south)

iii) Work out the rate of gain of gravitational potential energy

MY WORKING

= GPE / 15.6 = (14715 x 25) / 15.6 = 23581.7 = 23600

MARKSCHEME

= GPE / 15.6 = (14700x 25) / 15.6 = 23520 = 24000

Obviously 2 wildly different answers, even though the method is almost the same. Obviously I don't want to throw away any marks because I've rounded too early/too late/ not enough/ too much, so if any one can inform me of if there's a set of rules to follow (or if markers are lenient) that would be great

ie can a chain of hydrogen/carbon molecules still be described as a hydrocarbon chain even if at points a few carbon-carbon double bonds are thrown in.

I know this question must seem stupidly simple but I'm doubting my logic and would just like some outside confirmation

A model car runs on a narrow flexible track. It has been formed into a vertical loop with radius r.

The car approaches the loop at speed u, and at the top of the loop, the car has a speed v.

U and V are linked by the equation

u(squared) = v(squared) + 4gr, where g is gravitational field strength and r is radius)

(This is derived from the equation KEstart = KE final + GPE)

There is a mininum value of u necessary for the car to reach the top of the loop, if it is under ROOT(5gr) the car will fall off the loop before reaching C. The minimum value for v, therefore, is ROOT(gr)

For a loop of radius 20cm, the track preceding the loop must be raised by 50cm, so that the car, when released from rest will have a value for u necessary to complete the loop. However, the boy playing with the car only has enough track to raise the end by 40cm. Calculate the mininum speed at which he must release the car to perform the stunt.

===

I know that there is a LOT of information there for one question, a lot of it was worked out from previous parts of the question I had no trouble with, just this last part has tripped me up. The textbook answer gives (1.4ms^-1) but I have no idea why that should be. If anyone could help me out that'd be great :)

The Binomial expansion of (2x + 5/x)^6 has a constant term. Find this term.

Out of guesswork, I deduced that the constant term would be where n = 3, since it was half of 6

I then said 6C3 x (2x)^3 x (5/x)^3

= 20 x (8x^3) x (5x^-1)^3

=160x^3 x 125x^-3

To then finish, I said

Coefficient

160 x 125 = 20,000

Power Laws

y^3 x y^-3 = y^0 = 1

so the term is 20,000. This was right, but apparently this is only the coefficient of x^3, and I don't understand why this is the case (See my power laws working).

If anyone could explain at what point in my working my logic was wrong, or whatever, I'd be very grate-full

You are given f(x) = 2x³ + 7x² + 7x - 12

Show that f(x-4) = 2x³ - 17x² + 33x

Is there an easier to way to work this out other replacing (x) with (x-4) and then going on to solve it? (Up until the equation they give you)

ie 2(x-4)³ + 7(x-4)² + 7(x-4) - 12

The question is only worth 3 marks and this method seems needlessly long.

I have a question that first asks you to determine the oxidation state of chlorine in chlorine gas, and molecule HClO from the equation

Cl2 = Cl- + HClO [irrelevant molecules omitted]

I said the oxidation state to begin with was 0, and it changed to +1 in HClO. Now, this seems to be correct but it was the next question that stumped me. It asked to do a half equation for chlorine that shows what happens when chlorine molecules become chlorine ions (Based on the above reaction).

I said Cl2 = Cl- + Cl+

However, up until now I have always assumed electrons, at some point, where essential in half equations (eg Cl2 + 2e- = 2Cl -) but I cannot find a way to fit them into the question and have it be correct, so I'm not confident in my answer. If I could just have a second opinion or a confirmation if my working is right/ wrong that'd be great/

Here are the questions themselves http://oi45.tinypic.com/15f5mv.jpg

I can do part 8b, I know how to work out the total resistance of multiple resistors in Parallel.

My main issue seems to be loops. I think my biggest issue is identifying loops and applying Kirchhoff's second law correctly. If you could go over your explanation rather than just answering that'd be great, so hopefully I'd be able to do different but similar questions by myself

A geometric progression has 2 possible values for the first term, a and common ratio, r

When a is 10, r is 0.6

When a is 15, r is 0.4

Show that the ratio of nth terms of the two geometric progressions can be written as

2^(n-2) : 3^(n-2)

I know that the sum to 'n' terms is || ar^(n-1) ||

No matter what way of looking at this question, I hit dead ends. I'd love it If someone could explain their logic as they go through the answer :)

Hey everyone, I would love an explanation on how to work out the following maths question

The function f(x) x^4 + bx + c is such that f(2) = 0.

Also, when f(x) is divided by x + 3, the remainder is 85.

Find values for b and c.

Hey, I'm stumped on this question

"When a high-resistance voltmeter is placed across an isolated battery, its reading is 3.0V. When a 10 ohm resistor is connected across the terminals of the battery, the volt meter reading drops to 2.8V. Use this information to determine the internal resistance of the battery" (Mark scheme answer: 0.71 ohms)

When it came to the lost volts section in electricity, the only part I really understood E = Ir + IR, so I'd appreciate explaining the steps you do to work out the answer :)

Calculate the oxidation number of Nitrogen in Ca(NO3)2

My working:

Ca= +2 therefore (NO3)2 = -2

therefore NO3 = -1

Let the oxidation number of N = x

x + (3(-2)) = -1

x + -6 = -1

x = 5

Therefore the oxidation number of nitrogen in Ca(NO3)2 is 5

I really have no idea how to do the question

1 - cos^2 x = 2sin x

my answer booklet gives the answer "0, 180, 360" but obviously I'd like to know how to do the question myself :)