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  1. J

    Dynamics (Help me understand)

    i can appreciate you comment. But this is what i mean. This isnt sinking in. My lectures speak to me like this. Could you work through it with me. Cheers
  2. J

    Dynamics (Help me understand)

    hey guys, i'm in the middle for revising for a dynamics paper in January. I'm in the middle of a 1st year BSc Physics degree. Looking through some past papers, there are questions that i can do, and there are questions that i am unable to do. These are usually question where you have to derive...
  3. J

    Adiabatics with OTTO CYCLE

    hey guys, just wanted to know, in the graph of the OTTO cycle in the link http://www.qrg.northwestern.edu/ther...Pv-diagram.gif [Broken] are stage (2-3) and (1-4) adiabatic or not, if so why are they the reason i ask is that i have a graph showing that these stages are adiabatic...
  4. J

    Kinetic energy of bullets

    you have not converted the mass of the bullet from grams to kgrams 0.50 x (3.5x10^-3) x 42.4^2 = 3.14J this is the answer i got
  5. J

    Adiabatics with OTTO CYCLE

    hey guys, just wanted to know, in the graph of the OTTO cycle in the link http://www.qrg.northwestern.edu/thermo/design-library/otto/Otto-Pv-diagram.gif are stage (2-3) and (1-4) adiabatic or not, if so why are they the reason i ask is that i have a graph showing that these stages are...
  6. J

    Maxima question needs checking

    question a rectangular plot of land requires fencing on all 4 sides. two opposite sides will use heavy duty fencing at £6/metre, whilst the other tow sides will use standard fencing at £3/metre. if the farmer buying the fencing has £5000 to spend, what is the maximum area he can enclose...
  7. J

    Are these correct

    1) Differentiate x(t) = pi / t2 pi x(t) = t-2 = pi (t-2) = -2pi t-3 2) Differentiate x(t) = 1 / (At3 + B) = (At3 + B)-2 x (2At2) = (-2At2) / (At3 + B) 3) Differentiate x(t) = [A sqrt(t+B)]4 = [A (t+B)1/2]4 = A4(t + B)2 = 2A4(t + B) 4) The nebraska board of grain are...
  8. J

    Are my dimensional analysis question correct

    for; v2/3A i got an answer of = L4/3T-2/3 is this correct
  9. J

    Trig identity question need checking

    1. cos(2x+y) = cos(a+b) = sinasinb + cosacosb = (2x+y) = sin2xsiny + cos2xcosy = sin2x = 2sinxcosx and cos2x = cos2x-sin2x = cos(2x+y) = (cos2x-sin2x)cosy - (2sinxcosx and cos2x)siny (is this correct) 2. evaluate the following exactly (use \sqrt{} in your answer where necessary) cos...
  10. J

    Logarithms questions need checking

    1. ln (x2 / y2) = log (A / B) = logA-logB = logx2-logy2 = 2logx - 2logy (is this correct) 2. can this expression be split into seperate log functions and numbers, is this question the answer log(2x + 3y) = log(2x + 3y) (is this correct)
  11. J

    Dimensional analysis question

    given a distance s = 8.6m, time t = 2s, and a mass = 1.01kg, evaulate the expression to a physically appropriate accuracy? m3 = 1.013 = 3.03kg is this correct
  12. J

    Are my dimensional analysis question correct

    are these dimensional analysis questions correct A = area V = volume v = speed p = density 1. VA / v = L3 L2 L-1 T-1 = L4T-1 2. V2/3 A = (LT-1)2/3 L2 = L2/3 T-2/3 x L2 = L10/3T-2/3 3. 3A3 + 2V2 = A3 = L6 V2 = (L/T)2 = L2T-2 = L4T-2 are these correct
  13. J

    Is these algebraic expression correct

    1.(x - 3)2 = 4 x2 - 6x + 5 = 0 (x - 1)(x - 5) = 0 x = -1, -5 (is this correct) 2. 2x + 4 / x +1 = x - 8 / 2x - 1 (2x + 4)(2x - 1) = (x - 8)(x + 1 4x2 - 2x + 8x - 4 = x2 - 7x -8 4x2 - 6x - 4 = x2 - 7x - 8 (where do i go from here) 3. (x / 3) - (y / 2) = -1 (y / 2) = -4 - 3x 6x + y...
  14. J

    Is this algebraic expression correct

    a(a-6) + 9 = 0 a2 - 6a + 9 = 0 (a - 3)(a - 3) = 0 a = -3 is this correct
  15. J

    Is this subtraction correct

    a gas contains 2 kinds of atoms 4x105atoms of type A and 8x105 atoms of type B. it is known that the mass of type A atoms is 5x10-26kg and the mass of the gas is 2.8x10-20kg. what is the mass of type B atom? answer; 2.8x10-20kg - 5x10-26kg = 2.8x10-20kg - 0.00005x10-20 = 2.799995x10-20kg...
  16. J

    Is this right

    questions 3. A substance consists of equal numbers of tow kinds of atoms, with masses m1 and m2 respectively. a) what is the mass of the substance is 2x106 atoms of each kind are present, where m1 = 3.4x10-26kg and m2 = 1.6x10-26kg? answer; 3.4x10-26kg + 1.6x10-26kg = 5x10-26 x 2x106 =...
  17. J

    Algrbra problem

    this is the question; (4y1/3 / x3 \sqrt{32x2 / 2\sqrt{y}})1-2 is this the correct answer; 2y1/12 4x3/70
  18. J

    Differentiation problem and finding maximum, need helping ?

    Differentiation problem and finding maximum, need helping :)? have a few problems with these questions, can you help :) Using differentiation, find the MAXIMUM value of the following functions? 1. f(x) = x2 / 4 + 4 / x 2. f(x) = xe-2x2 3. f(x) = sqrt(x - n) / x ; n>0 hope you guys...
  19. J

    Indefinate integration problem

    Indefinate integration problem !! find the following indefinate integrals? a) ∫ x / 1 + x2 b) ∫ 1 / 1 - x2 c) ∫ 3x / (2x2 - 3)4 can you help me please !!!
  20. J

    Indefinate integration problems

    Indefinate integration problems!!! find the following indefinate integrals? d) ∫ 6x2 / sqrt(2x3 + 9) e) ∫ x sqrt(1 - x2 f) ∫ 4 / (x + 2)(x + 3) can you help me answer these please
  21. J

    Maximum values for differentiation

    maximum values for differentiation :( have a few problems with these questions, can you help :) using differentiation, find the maximum value of the following functions? 1. f(x) = -x2 + x 2. f(x) = lnx - x 3. f(x) = -x2 + 2x2 4. f(x) = x2/4 + 4/x 5. f(x) = xe-2x2 6. f(x) = sqrt(x -...
  22. J

    Differentiation problems

    hey guys, i do apologise, i had a go at them, and i was wondering if the answers i got were correct! 1.f(x) = -x^2 + x d/dx(x^n) = nx^(n-1) f '(x) = -2x + 1 2.f(x) = lnx - x f '(x) = (1/x) - 1 3.f(x) = -x^4 + 2x^2 f '(x) = -4x^3 + 4x 4.f(x) = x^2 / 4 + 4 / x...
  23. J

    Differentiation problems

    have a few problems with these questions, can you help :) 1. f(x) = -x2 + x 2. f(x) = lnx - x 3. f(x) = -x4 + 2x2 4. f(x) = x2/4 + 4/x 5. f(x) = xe-2x2 6. f(x) = sqrt(x - n)/x ; n>0 hope you guys can help !
  24. J

    Last question on integration (and i am stuck)

    that is what the question says on my sheet mate, im sure i aint dyslexic and it is the bloody lectures that cant write down questions properly haha
  25. J

    Last question on integration (and i am stuck)

    bare with me, i am a diagnosed dyslexic sorry, i know what a head land is, but i can not seem to go anywhere, im not comprehending this info lol
  26. J

    Last question on integration (and i am stuck)

    in plan view, the shoreline of a bay may be approximated by a curve f(x) = -x2 + 2x between one headland at x = 0 and another at x = 1km, where (f) is also measured in km. at low tide, the edge of the sea just reaches each headland, following a straight line between them. calculate in km2 the...
  27. J

    What is the derivative of this

    what would be the derivative if you are asked to differentiate x(t) = pi / t^2
  28. J

    If a person breathes thirty time in a minute what is ?

    if u wana find the frequency, which is the number of cycles per second, find out how many breaths u take in 1 sec and put it in2 the formula, it is basic conversion thats all, it is easier that you think, just stop thinking "complicated", think basic :) hope this helps :)
  29. J

    What is the derivative of this

    hey guys whats is the derivative of you are asked to integrate; x(t) = pi / t2 i dont have a rule for this, so i cant integrate it :( help
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