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# Year 13 Maths Help Thread Watch

1. (Original post by Coolsul98)
Q) "The diagram shows a particle of mass 0.5 kg resting on a rough plane inclined at 30 (degrees) to the horizontal. The coefficient of friction between the particle and the plane is 0.4. A of force of magnitude PN, acting directly up the plane, is just sufficient to prevent the particle sliding down the plane. Find the value of P."
Do you know how to resolve forces?
2. (Original post by B_9710)
Do you know how to resolve forces?
Yeah did that for Fgrav and added it to the Coefficient of friction but my answer is way off. P=0.768 in the mark scheme. Im not sure how they arrived to that answer
3. http://www.physicsandmathstutor.com/...nbank/question 9c exercise 2cWhy is the (pX>n)>0.99 not the probability its greater or equal to as if they have a number of boats equal to the amount demanded is that not sufficient to meet all demands so why is it just greater than n as i thought it cud equal n too if n are demanded
4. http://files.physicsandmathstutor.co...hapter%202.pdf
s2 question 9c exercise 2c
Why is the (pX>n)>0.99 not the probability its greater or equal to as if they have a number of boats equal to the amount demanded is that not sufficient to meet all demands so why is it just greater than n as i thought it cud equal n too if n are demanded
If first link dont work its chapter 2 s2 http://www.physicsandmathstutor.com/...-solutionbank/
5. (Original post by B_9710)
Do you know how to resolve forces?
Wouldn't it just be ??
6. (Original post by youreanutter)
http://files.physicsandmathstutor.co...hapter%202.pdf
s2 question 9c exercise 2c
Why is the (pX>n)>0.99 not the probability its greater or equal to as if they have a number of boats equal to the amount demanded is that not sufficient to meet all demands so why is it just greater than n as i thought it cud equal n too if n are demanded
If first link dont work its chapter 2 s2 http://www.physicsandmathstutor.com/...-solutionbank/
SeanFM You know stats, don't you?
7. (Original post by youreanutter)
http://files.physicsandmathstutor.co...hapter%202.pdf
s2 question 9c exercise 2c
Why is the (pX>n)>0.99 not the probability its greater or equal to as if they have a number of boats equal to the amount demanded is that not sufficient to meet all demands so why is it just greater than n as i thought it cud equal n too if n are demanded
If first link dont work its chapter 2 s2 http://www.physicsandmathstutor.com/...-solutionbank/
Handy tip, at the end of a pdf link if you type #page6 for example, it will take the reader to page 6 immediately.
8. (Original post by RDKGames)
Wouldn't it just be ??
I did exactly that! But the Mark scheme sais that P=0.768 i have no clue how
9. (Original post by ValerieKR)
you're on the right lines
The Bernouilli question is the most approachable out of the three you gave me; I can't even make a start on the others (I have only done C1-C4 so that may be why)! I'm not going anywhere near STEP II again until I have done at least 50 STEP I questions on my own (which won't happen until maybe March).

My aim is to do the relatively easier STEP I questions first so that I can pick up enough tricks to help me with the trickier ones.
10. (Original post by Coolsul98)
Q) "The diagram shows a particle of mass 0.5 kg resting on a rough plane inclined at 30 (degrees) to the horizontal. The coefficient of friction between the particle and the plane is 0.4. A of force of magnitude PN, acting directly up the plane, is just sufficient to prevent the particle sliding down the plane. Find the value of P."
0.5gsin30-(0.4*0.5gcos30)=P
11. (Original post by RDKGames)
Wouldn't it just be ??
No it's 0.5gsin30-(0.4*0.5gcos30). It's on the point of moving down the slope so friction is up the slope
12. (Original post by metrize)
No it's 0.5gsin30-(0.4*0.5gcos30). It's on the point of moving down the slope so friction is up the slope
Weird to determine in which direction it is if it's not actually moving. I'm now just assuming that it is going down the slope, so the friction force acts in the same direction as P before it is considered, and the sum is equal to the gravity pulling it down. Then just start considering P and the particle starts slowing down to a stop while friction still acts in the same direction.
13. (Original post by RDKGames)
Weird to determine in which direction it is if it's not actually moving. I'm now just assuming that it is going down the slope, so the friction force acts in the same direction as P before it is considered, and the sum is equal to the gravity pulling it down. Then just start considering P and the particle starts slowing down to a stop.
In the question it says P is the force that stops it from moving down the plane so the friction is in the same direction as p
14. (Original post by Palette)
The Bernouilli question is the most approachable out of the three you gave me; I can't even make a start on the others (I have only done C1-C4 so that may be why)! I'm not going anywhere near STEP II again until I have done at least 50 STEP I questions on my own (which won't happen until maybe March).

My aim is to do the relatively easier STEP I questions first so that I can pick up enough tricks to help me with the trickier ones.
And at the end of this year?
15. (Original post by ValerieKR)
And at the end of this year?
Well I find STEP I questions much more manageable this time around than how I found them when I first learnt C3/C4 half a year ago. I can round up all the 'nicer' questions and then work my way up the difficulty level- essentially tackling STEP 'step by step' (apologies to Zacken for copying his pun).

My aim is to do as many STEP questions as possible until I start university maths next September/October to make the transition from A level to uni as smooth as possible.

But MAT is more important than STEP at the moment!
16. (Original post by Palette)
But MAT is more important than STEP at the moment!
You're not applying to Oxford, are you? -.-
17. Guys, I have a question.
How do you remember all the trig identities and differentiation methods (chain, product and quotent rule) (for Edexcel c3)
I find myself always having to look for the identity so I know which one to use
18. (Original post by asinghj)
Guys, I have a question.
How do you remember all the trig identities and differentiation methods (chain, product and quotent rule) (for Edexcel c3)
I find myself always having to look for the identity so I know which one to use
Practice.
19. (Original post by asinghj)
Guys, I have a question.
How do you remember all the trig identities and differentiation methods (chain, product and quotent rule) (for Edexcel c3)
I find myself always having to look for the identity so I know which one to use
Practice a lot.
20. (Original post by asinghj)
Guys, I have a question.
How do you remember all the trig identities and differentiation methods (chain, product and quotent rule) (for Edexcel c3)
I find myself always having to look for the identity so I know which one to use
I have perfect recall.
Spoiler:
Show
Practice.

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Updated: June 26, 2017
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