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  1. 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...
  2. 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...
  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/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...
  4. 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...
  5. 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...
  6. 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...
  7. 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)
  8. 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
  9. 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
  10. 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...
  11. 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
  12. 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...
  13. 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 =...
  14. 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
  15. 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...
  16. 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 !!!
  17. 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
  18. 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 -...
  19. 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 !
  20. 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...
  21. 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
  22. J

    Integration problem (need help)

    if a spaceship accelerates, from restat time t = 0, at a rate of 2t / sqrt(1 + t^2) m/s at time t, calculate in years to 1 significant figure how long it would take to reach the speed of light? my attempt speed of light = 3.0 x 10^8 m/s integrate the rate function 2t / sqrt(1 + t^2) from...
  23. J

    Finding the rate of change

    the height h(x) in meters above the ground of a parachute varies with her horizontal distplacement x in meters from a landing target on the ground as h(x) = 50sin^-1 (0.1x). what is the rate of change of h with respect to x at x = 6m? i was wondering of someone could help me with this question :)
  24. J

    Finding Ohm law values

    how do i go about answering this question guys, send me in the right direction please :) "when a diode allows a positive current to flow it has a resistance of 0.5kohms. It does not allow negative flow, i.e. the resistance is infinate. using ohms law, sketch a graph of current I against...
  25. J

    Graph problem

    hey guys, stuck on a few question, but dnt tell me the answer, direct me please :) how do i find the intercepts for; 1. y = 1 / x -1 2. y = 2 / x + 1 3. y = 3 / 2x + 3 cheers guys :):)
  26. J

    Using quadratic formulae

    hey guys, could u use the quadratic formula; x = -b +/- sqrt (-b2 - 4ac) 2a for the following questions; y = 4x2 - x y = 4x2 -1 y = x2 + 4 and y = -2x2 + 4x i ask this as there is no value for (c)...
  27. J

    Spaceship calculus problem

    if a spaceship accelerates, from rest at time t=0, at a rate of 2t / sqrt(1 + t2) ms-2 at time t, calculate in years to 1 significant figure how long it would take to reach the speed of light 3x108 ms-1? i got an answer of 5 years, is this correct, but i have made a mess of my workings, what...
  28. J

    Log questions i need help with

    i need help with the following quesitons; a) log_3 27x^2 b) ln (x^2 / y^2) c) ln (xe^x) d) log (2x + 3y) i dont mind if you could direct me in the right direction and i will do my best to go from there :) USING THE RULES FOR LOGS, SPLIT THE FOLLOWING UP INTO SEPERATE...
  29. J

    Log with base 3 or other bases

    hey guys, i have a question, then i will show my solution, is there any chance you guys could help me find an easier way to get to the answer, cheers question: log_3 3x answer: log_a (yx) = log_a (y) + log_a (x) log_3 (3) + log_3 (x) log_a (y) = x -> y = a^x -> log_a (a) = 1...
  30. J

    Exponential relationships to logarithms and straight line graph?

    it is suspected that cells in a sample are dividing so that the number of cells present at any one time t (measured in seconds) is growing exponentially according to the relationship y = 64 x 2^2t. it would be hard to check this relationship accurately by plotting measurements of y against t, so...
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