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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

    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
  4. J

    Adiabatics with OTTO CYCLE

    hey guys, just wanted to know, in the graph of the OTTO cycle in the link 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...
  5. J

    Are my dimensional analysis question correct

    for; v2/3A i got an answer of = L4/3T-2/3 is this correct
  6. 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
  7. 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
  8. 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...
  9. 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 =...
  10. 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
  11. 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 :)
  12. 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...
  13. J

    Using quadratic formulae

    cheers tiny-tim, thanks, ill use those :)
  14. 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)...
  15. J

    Help with Dimensional Formulae

    hey guys, i can see where u are coming from, i spend an hour or 2 just going through questions and found that if you know the formula for of something for example (Force) = m x a, then is is just stripping it down to its most basic units, m = M and being that a = change in velocity per unit time...
  16. J

    Log questions i need help with

    Using the rules for logs, split the following up into seperate logarithm functions and numbers as much as possible?
  17. 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...
  18. 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...
  19. J

    Specific heat capacity

    all i know as specific heat capacity is = Q / M (theta), there is an inverse effect on theta (temperature) and specific heat capacity, as temp increases SHC decreases!
  20. J

    Exponential relationships to logarithms and straight line graph?

    cheers mate, i wasnt doing that, i think i need to spend more time and concentration on logs and try a number of different questions on it, thanks again
  21. 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...
  22. J

    Help with Dimensional Formulae

    ah i see, m = M, v^2 = L^2 T^-2 SO ENERGY SHOULD BE; ML^2T^-2
  23. J

    Help with Dimensional Formulae

    there are many equations for energy, dont know what one to break down into its dimensions!!
  24. J

    Help with Dimensional Formulae

    hey guys, i was wondering if you guys could help me with a few things. 1st, how to work out dimensional formulae questions, i can not get my heard around it, and im sure with some help i can nail it, help; how do u give the dimensions for ENERGY and give the dimensions of the...