Base Definition and 586 Threads

  1. M

    Solved C Program: Basic Angle Calculation

    (*sovled) basic C program problem Homework Statement attrached. and one more thing is: if the angle is 90, a statement "This is a right angle." should be appeared in the last rows, else, "This is not a right angle" instead. also, the degee is 90 (interger) but not 90.0 Homework...
  2. B

    Is the pH of an acidic buffer affected by incomplete dissociation of the salt?

    Hi ! i am new to these forums.. so i just want to ask whether i am posting my query in the correct forum?? I have a doubt regarding this weak acid - weak base buffer. When the moles of Acid > Base, We use the formula pH = pka + log10 ([salt]/[acid]) to calculate the pH of the Acidic Buffer...
  3. X

    How far does Sam land from the base of the cliff?

    Sam (60 kg) takes off (from rest) up a 50 m high, 10° frictionless slope on his jet-powered skis. The skis have a thrust of 200 N. He keeps his skis tilted at 10° after becoming airborne, as shown in Figure P6.43. How far does Sam land from the base of the cliff? a=F/m I used 50/sin10 to...
  4. T

    Converting between base 7 to 3

    Homework Statement convert (352416)_7 to (...)_3 the _7 means base 7 and similarly, _3 means base 3. Idea : convert base 7 to base 10 then base 10 to base 3. I know I can use expansion, 3 * 7^6 + 5 * 7^6 ... to convert it to base 10. but in my exam, we are not allowed to use...
  5. A

    What is the maximum base current for a BJT NPN transistor and how can I find it?

    in BJT transistors how can I find the maximum base current? Do we have maximum voltage limitation for base of transistor? consider a resistor between input and base of transistor. I want to use a transistor that its input range is from 3 to 30 volts and its output is 5 volts. how can i do...
  6. tony873004

    LOG Base: 10, e, or Other - What Does it Mean?

    If I see a formula that contains LOG, but does not specify as base, how do I know what base they're referring to? Programming languages assume LOG means base e. My calculator assumes LOG means base 10. I've seen math teachers assume it meant base e. If its base anything other than 10 or e...
  7. R

    Trajectory of a Baseball: Will it Clear the Fence?

    Now I'm seriously just tired and can't get these, but I don't know why this is wrong at all. This would help if I had a study partner in my physics class (to bounce ideas off of), but no one else in my class is overly strong in the subject. Homework Statement A batter hits a pitched ball...
  8. M

    Expressing the Solution of 2^(2x+3) = 2^(x+1) + 3 as a + log2b: Complex Numbers

    Homework Statement The solution of 2^(2x+3) = 2^(x+1) + 3 can be expressed in the form of: a + log2b where a, b belong to the set of complex numbers. The Attempt at a Solution (2^3)(2^x)^2 = 2^(x+1) + 3 [8((2^x)^2)] - [2(2^x)] - 3 = 0 Solving the above quadratic for 2^x, I...
  9. T

    Number Base System: Solving the Radix/Base

    Homework Statement This really isn't a calc question so forgive me. Determine which base(radix) is used in the following operation : a ) 1234 + 1234 + 1234 + 1234 = 11101 b ) 19 * 18 = 297 I know the answer to a but am not sure how to get it. What I see is the for a) the answer...
  10. C

    Comparing Basicity: -OCH3, -OH, -NH2, and Alkyle with Negative Charge

    Homework Statement -OCH3, -OH, -NH2, and the fourth choice is an alkyle, ethyne with a neg charge. the picture shows a triple bond attacked to a hydrogen. Homework Equations The Attempt at a Solution I know that OH is a relatively common base and I thought it was strong, but I...
  11. H

    Why Does the Common Base Amplifier Model Show a Steep Rise and Offset?

    Greetings. I am trying to understand the common base amplifier better so I can build a preamp for a low impedance guitar pickup. In order to explore its operation, I tried to model it with the "approximated" Ebers-Moll model (from the wikipedia page on BJT's) and the graphing program in Mac OSX...
  12. S

    Identifying the Strongest Base: Comparing NH2-, OH-, Cl-, NH3, and I-

    Homework Statement Which of the following species is the strongest base? A. NH2- B. OH- C. Cl- D. NH3 E. I- Homework Equations The Attempt at a Solution Ok I know that Cl- is a very weak base so I know it is not that one for sure. I want to say that the answer is NH2-...
  13. S

    BJT Base Transit Time: Understanding the Basics

    Hi to you all, I'm reading about semiconductor devices on Muller-Kamins' "Device Electronics for Integrated Circuits" and I have some problem understanding the base transit time of a bipolar transistor. I read that when the npn bjt is forward biased the emitter injects electron in the base. In...
  14. S

    Logarithm with Different Base: Solving for x/y

    Homework Statement Hi everyone I need help for this problem : If 2*\log_2 (x-2y)=\log_3 (xy) , find \frac{x}{y} Homework Equations \log_bx = \frac{\log_ax}{\log_ab} The Attempt at a Solution 2*\log_2 (x-2y)=\log_3 (xy) \log_2 (x-2y)^2=\log_3 (xy) \frac{\log_2...
  15. J

    Convergent Filter Base and Continuous Function

    Hi All, I can't see how the following is proved. Given two topological space (X, T), (Y, U) and a function f from X to Y and the following two statements. 1. f is continuous, i.e. for every open set U in U, the inverse image f-1(U) is in T 2. For every convergent filter base F -> x, the...
  16. J

    Easier Way to Simplify log_3 3x?

    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...
  17. 3

    Calculating upright loads to base plate

    Hello PF I hope you can give me some guidance. This is something that I am getting more and more on my desk, to be honest I don't understand it enough to give an answer. I have searched the net looking for an answer but can only find details on fulcrum points class 1,2 & 3 which does not seem to...
  18. T

    Big-O With Change of Base for Log

    Homework Statement Hi, I am trying to prove for a>1, b>1 that f(x) = O(log_b(x)) then f(x) = O(log_a(x)). [Hint: log_b(x) = log_a(x)/log_a(b)). Homework Equations The Attempt at a Solution Assuming |f(x)| <= C|log_b(x)| true for x>k, then, f(x) <= log_a(x)/log_a(b)| for all x>1...
  19. M

    Differentiation With 'x' Both in Base and in Exponent

    I have just begun studying differentiaition and I was getting confused with how to differentiate a function of x in which x is in the base and is in the exponent as well (for example, x^2x) with respect to a=hte cahnge in 'x'. I remember my teacher telling me something about applying log...
  20. B

    Common base amplifier current gain

    Hi folks - I'm trying to follow along in a textbook the derivation of the common-base current gain equation, and I'm having a bit of trouble. The common base current gain is supposed to be approximately \alpha, where \alpha = \frac{\beta}{\beta+1}. Doing a nodal analysis with the signal applied...
  21. D

    How to distribute product sign across base and exponent terms

    I am calculating the likelihood of a hierarchical model and am having trouble distributing the product sign. Here are the two expressions that I'm interested in: Product from j=1 to j_k of: (t_jk)^(sum(Z_ijk) + a_k - 1) and Product from k=1 to K of: (b_k)^(j_k*a_k). The tricky...
  22. D

    How to distribute product sign across base and exponent terms

    I am calculating the likelihood of a hierarchical model and am having trouble distributing the product sign. Here are the two expressions that I'm interested in: Product from j=1 to j_k of: (t_jk)^(sum(Z_ijk) + a_k - 1) and Product from k=1 to K of: (b_k)^(j_k*a_k). The tricky...
  23. D

    Converting Error in Log2 Form for Arbitrary Base

    Hi, I am trying to represent my data in log2 form rather than "fold change" and I am embarrassed to say I can't remember how convert the error. For example, I have x=3.96 (mean), deltax=0.28 (standard dev). Thus, log2(x)=0.598. But how do I convert the error?? I know how to do it for...
  24. R

    Forward resistance of the Base -Emmiter Junction?

    Homework Statement Forward resistance of the Base -Emitter Junction showed a value of 12ohms when it was measured by (x1) resistance scale of an analogue multimeter .And it showed 70ohms when it was measured using (x 10) scale factor .The variation in the two readings occurs due to...
  25. T

    Na3PO4 or C2H4(OH)2: Which Produces pH Curve?

    Homework Statement Which of the following, Na3PO4 or C2H4(OH)2 could produce a pH curve with two buffer zones? The Attempt at a Solution I think the answer is Na3PO4 because it can react twice, but the third reaction may not complete. C2H4(OH)2 is ethylene glycol. Is it possoble for it to...
  26. D

    Calculating base ionization constant from a known pH and concentration

    Homework Statement In this experiment you will find the ionization constant for ammonia, a weak base. I have completed the experiment, and have the following: Initial concentration of NH3: 3.708mol/L Initial pH of NH3: 10.26 Homework Equations NH3(aq) + H2O(l) <--> NH4+(aq) +...
  27. P

    Solution check for pH of Strong Acid and Strong Base

    Homework Statement Calculate the pH after 24 mL of 1.00 M NaOH is added from the burette to a beaker containing 25.0 mL of 1.00 M HCl Homework Equations pH = -log [H+] 1*10^-14 = [H+][OH-] The Attempt at a Solution combined volume = 49mL n.unreacted(H+) = 0.025-0.024 = 0.001...
  28. W

    Plotting Base Characteristics in Mathematica w/ Equations & Initial Data

    Homework Statement I am trying to plot base characteristics using mathematica. The characteristic equations are: Homework Equations \frac{dx}{d\tau}=x u(x,y) \frac{dy}{d\tau}=y u(x,y) \frac{du}{d\tau}=x^2+y^2 u(x,1)=Sqrt(x^2+1) Initial Data The Attempt at a Solution How do I solve this...
  29. I

    Deriving the load point on equipment base

    Homework Statement Problem is this. I am tasked with deriving a formula or equations that I can then input into an excel format. I am to take an equipment base that has four sides with supports at each of the four corners. I am to find the load that each one will hold base upon the Center of...
  30. S

    Is NaHCO3 a versatile compound in aqueous solutions?

    Homework Statement Write two equations that illustrate that an aqeous solution of NaHCO3 can act either as an acid or a base. In pure water show quantitatively which of the two reactions predominate. ka1= 4.2x10-7, Ka2=4.8x10-11 The Attempt at a Solution as an acid: NaHCO3(aq) +...
  31. C

    Is a Space Station More Cost-Effective than a Moon Base?

    Why is the idea of putting a station in orbit more appealing then putting on on the moon? I understand the want to test things in low gravity. But what about cost wise? I know that the ISS has to change it's direction every now and then to avoid random junk floating in space, and I understand...
  32. K

    Seven digit base eight positive integer puzzle

    N is a seven digit base-8 positive integer having the form ABCDEFG that uses each of the nonzero base-8 digits 1 to 7 exactly once, and satisfies these conditions: (i) ABCDEFG is divisible by 7. (ii) ABCDEF is divisible by 6. (iii) ABCDE divisible by 5. (iv) ABCD is divisible by 4. (v)...
  33. A

    Determine the base unit for the magnetic flux

    Homework Statement The e.m.f E of a battery is given by E = \frac{P}{I} where P is the power supplied from the battery when current I flows through it. An e.m.f. {E_c} can also be induced in a coil when the magnetic flux, \Phi , associated with it changes with time, t, as expressed by {E_c} =...
  34. T

    Find orthogonal base for u+v without answer

    i got these vectors R4: v1=(1,1,0,1) v2=(0,-4,2,0) v3=(0,0,-18,0) u1=(1,1,0,1) u2=(-1,0,1,0) in the row reduction process v1 v2 v3 u1 are left independent i need to find the orthogonal base of u+v? in the solution i was told that because v1 v2 v3 u1 are independent then the...
  35. M

    PH of buffer with addition of conjugate base

    Homework Statement Consider 1L of a solution that is 0.100 M in acetic acid and 0.100 M in sodium acetate. What will the pH be, when 0.0900 mol of sodium acetate are added? Ignore changes in volume. acetic acid pka = 1.75 E-5 Homework Equations HA --> H+ + A- pH=pka +log A-/HA...
  36. A

    Why the base of an electric iron is made thick and heavy?

    Why the base of an electric iron is made thick and heavy?
  37. B

    Converting rational number to a new base.

    Hello, I found one excercise - convert a rational number 63/64(base - 10) to a number system with a base of 4 using Radix conversion. Searching throught the internet i found this formula (i hope it`s the correct one :) ) - http://img255.imageshack.us/img255/903/races3.jpg Unlike...
  38. B

    Permanent Magnet Hoverboard and base?

    G'day. I was wondering about the possibilities of making a permanent magnet hoverboard that levitates above a permanent magnet floor. They say that these new neodymium magnets can attract hundreds of kilos/pounds. Since repulsion and attraction forces are the same magnitude from what I hear, why...
  39. F

    Solving Log Base Homework: 3 = Log2x 64

    Homework Statement 3 = Log2x 64 Homework Equations N/a The Attempt at a Solution 3 = Log2x 64 2x3 = 64 x3 = 32 x = Cubic root of 32 x = 3.1748 I'm fairly certain the answer has to be 2 b/c 2x would be equal to 4, and 43 = 64. Anyone mind helping me on this one? Probably...
  40. M

    Weak acid/strong base titration (Acetic acid/NaOH)

    I did an acid/base titration with acetic acid and sodium hydroxide to determine the concentration of acetic acid present in vinegar but I'm not quite sure how to go about calculating the concentration of it. First things first we dissolved 25ml of vinegar into 250ml of water and filled the...
  41. S

    What is the [H3O+] When Mixing Formic Acid and NaOH?

    Homework Statement 800ml sample of 2.00 molar formic acid HCOOH (or HA) ismixed with 200ml of a 4.80 molar NaOH. Calculate the [H3O+] of the resulting solution. Homework Equations (for buffers) pH=pKa-log(HA/A-) Ka for formic acid is 1.8x10-4 pH=14-pOH [H+]=(1.00x10-14)/([OH-) The...
  42. J

    Store Thousands of Letters on Computer: Best Ways

    I wish to store thousands of letters onto a computer for a friend. What is the best way to do this? Use Access, or write a program in C/C++ to store and fetch the letters onto CDs. Any suggestions gratefully received, as I have no idea how to get started on this.Thank you very much.
  43. pellman

    How does a fibre bundle differ from base space X typical fibre?

    Let's take a simple example. Both a cylinder and Möbius strip consist of a circle with a line segment associated with each point of the circle. The cylinder is considered truly equivalent to the direct product S1 X line segment while the Möbius strip is only locally like S1 X line segment...
  44. W

    Why purine-purine and pyrimidine-pyrimidine base pairs

    In DNA, the base pairs are on the inside of the heli. Eplain why purine-purine and pyrimidine-pyrimidine base pairs do not occur, only purine-pyrimidine base pairs?
  45. M

    Unpacking the Meaning of Specific Heat Capacity in Base Units

    specific heat capacity is measured in joule per gram-kelvin (J g–1 K–1). In base units it is m2 s-2 k-1. Is that meaningless to express specific heat capacity in base units? Is there an explanation? Thanks Nick
  46. K

    Frequency responce in a common base amplifier

    How the voltage gain of the amplifier depends on the frequency of ac signal. please explain. what is the role of coupling capacitors? how voltage gain is effected in mid , high and low frequency range? thanks.
  47. A

    Ammonia acts as a base in aqueous solution

    Homework Statement Ammonia acts as a base in aqueous solution; Kb is equal to 1.8 x 10-5. What is the Ka for the ammonium ion NH4+ in aqueous solution? Homework Equations The Attempt at a Solution I am totally lost for this question, can someone please start me off? all i know...
  48. M

    Calculating Concrete Materials for 1.68m³ Base

    Homework Statement hello I have to make a concrete base in metres cubed total 1.68 metres cubed. The ratio to concrete is 1 part cement to 2 parts sand and 3 parts gravel. how much cement,gravel, and sand in kilograms? Homework Equations ? The Attempt at a Solution ?
  49. N

    Calculating pH of a Buffer Solution with Added Strong Base

    Homework Statement Calculate the pH after 0.030 mol NaOH is added to 1.00 L 0.100 M HC3H5O2 and 0.100 M NaC3H5O2 Homework Equations Ka=[H+][A-]/[HA] pH=-log([H+]) or 14-pOH=ph The Attempt at a Solution HC3H5O2 <-> H+ + C3H5O2- NaC3H5O2 <-> Na+ + C3H5O2- I know that Na+ has no...
  50. I

    How to Solve Log Equations with a Variable Base

    Homework Statement Log [with base x]216 =6 Find x Homework Equations The Attempt at a Solution Ok, so I put the log equation into exponential form. It now becomes: x^6=216 I'm lost on what to do next.. I've tried taking the e and ln of both sides, but when I check it, it's...
Back
Top