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  1. H

    Convection question

    Hi, I was wondering if someone could help explain how the following shapes would affect convection. What it is is a heat plate with nothing, a bundle of tubes, and just fins. It's in a vertical tube and the air flows upwards. I understand convection but I don't get how it would be affected in...
  2. H

    Chemical Equilibrium

    Homework Statement The following reaction initially contains [A]o = 0.2150 M and [B]o = [C]o = 0.4150 M. If the equilibrium constant for the reaction is Keq = 2.03, what are the concentrations of reactants and products when the reaction has achieved equilibrium? What is the value of deltaG for...
  3. H

    Gas Stoichiometry

    Homework Statement A sealed 1.00 L vessel contains 0.3475 g of argon gas and 6.766 g of an unknown gas at 350 K. If the total pressure of the gas mixture is 2.56 atm, and the unknown gas has an empirical formula of CH2, what is the molecular formula of the unknown gas? Homework Equations I...
  4. H

    Mathematica Maple/Mathematica Help

    1. Consider a rectangular water tank with a length of 8m, a width of 4m , and a height of 5m. Water exits the tank by pouring over the sides. a) If the tank is initially full of water, find the work required to empty the tank. b) If the tank is initially half-full of water, find the work...
  5. H

    Maple + MVT help

    I figured out the 2nd one ^^ Just need help with the differentiation one.
  6. H

    Maple + MVT help

    I just have two questions: A fundamental problem in crystallography is the determination of the packing fraction of a crystal lattice, which is the fraction of space occupied by the atoms in the lattice, assuming that the atoms are hard spheres. When the lattice contains exactly two...
  7. H

    Silly question but uhh

    oh okay. Thanks.
  8. H

    Silly question but uhh

    How can I calculate cos ^2 (53)?
  9. H

    Epsilon Delta proof help

    It should be e / 1, since the limit is approaching -2, then -1 < x+2 < 1, or x+2 < 1, so delta = 1 and e / 1 ?
  10. H

    Epsilon Delta proof help

    Then it'd be delta = e / 0
  11. H

    Epsilon Delta proof help

    since it's a value close to -2, can we assume that it is within a distance 1 from -2, that is, -1<x+2<1 , -3 < x < -1 Here's where I was confused: Do I add 1 since the other value was x + 1? so, I'd be -2 < x + 1 < 0 ?or x + 1 < 0 ?
  12. H

    Epsilon Delta proof help

    We need to find such a number that restricts x to lie in some interval centered at 2, right?
  13. H

    Epsilon Delta proof help

    I get delta = min {1, e/0}
  14. H

    Epsilon Delta proof help

    I thought that was enough...where did I go wrong?
  15. H

    Epsilon Delta proof help

    I'm supposed to prove that lim x -> -2, x^2+3x+7 = 5 Here's what I have: |x^2 +3x+7 – 5| < ε |x+2| < δ |x^2+3x+2| -> |(x+2)(x+1)| < ε whenever |x+2| < δ |x+1||x+2| < δ |x+1| |x+1||x+2| < δ|x+1| < ε ε / |x+1| > δ , as x -> -2, |x+1| -> 3, therefore: ε / -1 > δ But...
  16. H

    True or false

    If a circle has an area of t square units and radius r, then a circle with an area of 2t square units has radius 2r.
  17. H

    Magnetic Fields problem set

    I'm having trouble with 4 questions and not sure how to go about starting to solve them. If anyone can give me help on how to approach these questions, it'd be really appreciated. I just put them all down at once rather then making separate threads. Thank you. 1) An electrical transmission...
  18. H

    Dot Product help

    -Use the dot product to prove that the quadrilateral with vertices A(-4,1) B(4,5) C(7,-1) and D(-1,-5) is a rectangle. I tried find AB dot BC = 0, but I'm not getting 0. So I'm stumped. Can someone help me out? =/
  19. H

    Hooke's Law and a spring

    Okay, I'll do that. I'll tell you how it goes tomorrow ^^
  20. H

    Hooke's Law and a spring

    Actually, that's why I'm here. I told him and he brushed me off, saying F=ma=kx <- Acceleration is constant. I actually just stormed out of the class and had a discussion with the VP about it. I just wanted to make sure I wasn't making a total ass of myself though. Thanks for your help :3
  21. H

    Hooke's Law and a spring

    It's a maximum acceleration
  22. H

    Hooke's Law and a spring

    Yes, I did too! See, my reasoning is, F=ma=kx, but k and m are constant, therefore when a greater force is applied to scretch the spring (or in this case, compress), acceleration changes (as well as x). However, the other two equations involves a uniform acceleration, which you can't have in...
  23. H

    Hooke's Law and a spring

    I used g, yes. and I did convert.
  24. H

    Hooke's Law and a spring

    Okay, I'm having a debate with my teacher. He's saying I'm wrong but I still think I'm right. The question is: What should be the spring constant, k, of a spring designed to bring a 1200kg car to rest from a speed of 100km/h so that the occupants undergo a maximum acceleration of 5.0g? He...
  25. H

    Gravitation (just to check if calculation is right)

    We haven't done integrals in this unit so I don't know how to solve that method =(
  26. H

    Gravitation (just to check if calculation is right)

    Hmm I think I rearranged the equation wrong then. Thanks.
  27. H

    Gravitation (just to check if calculation is right)

    I was wondering if someone could tell me if I did this right: Two neutron stars are separated by a distance of 10^10m. They each have a mass of 10^30kg and a radius of 10^5m. They are initially at rest relative to each other. How fast are they moving when they collide? R = 2r + d =...
  28. H

    Geometry Help

    They would intersect on the midpoint of the hypotenuse, right?
  29. H

    Geometry Help

    The vertices of a triangle are P(-3,1,2), Q(1,-3,-1) and R(3,-1,-1) -Verify that it is a right angled -Determine the area -Determine the perimeter -What are the coordinates of S(x,y,z) such that PQRS is a rectangle I'm not sure how to start to go about solving this problem. Could...
  30. H

    Momentum problem

    Two balls A and B having different but unkown masses collide. A is initially at rest and B has a speed v moving North. After collision B has a speed v/2 and moves perpendicular (East) to the original motion. Find the direction of motion of A after collision. Is it possible to determine the speed...
  31. H

    Equilibrium Problem

    nvm I think you meant 118. if you divided 188, you get 61 degrees.
  32. H

    Equilibrium Problem

    Wait how did you get -188 for the vertical?
  33. H

    Equilibrium Problem

    uhmm...thanks for telling me the answer, but it's useless if I don't know how to get the answer =(
  34. H

    Equilibrium Problem

    I'm supposed to find the equilibriant force on the diagram I posted (see attachments)
  35. H

    Equilibrium Problem

    Actually, I think I figured it out but are the vertical and horizontal forces correct? Or do the Fh and Fv should cancel out
  36. H

    Equilibrium Problem

    As you can see in the attachmen, I'm supposed to find the equilibriant force and the force from the left side. So is it something like this: Fx = 0, Fh + 200cos20-100cos30=0 Fh = -101.33N Fy = 0 Fv + 200sin20 + 100sin30 = 0 Fv = -118N But I get stuck on the rest. Can someone...
  37. H

    Balancing Forces

    For the second question, should I resolve the vectors into x and y then use the distances to find sigma t?
  38. H

    Balancing Forces

    I'm having trouble with two problems and I was hoping if someone could point me in the right direction go about solving them: 1) Two beams support a 4.0kg pail of water above an open well. How much compression force is exerted on each beam by the water pail, what outward force do the two...
  39. H

    Crate motion question

    Just wanted to make sure if I did this right: Two crates of mass 12kg and 20kg are pushed across a smooth floor together, the 20kg crate in front of the 12kg crate. Their acceleration is 1.75m/s^2. What is the action reaction force between the crates? F=ma F=(32)(1.75) F=56N then F...
  40. H

    Kinetic Motion

    Okay. Thanks for confirming my answers
  41. H

    Kinetic Motion

    Also, for this question: The Easter Bunny runs along a straight and narrow path with a constant speed of 25m/s. He passes a sleeping tortoise, which immediately starts to chase the bunny with a constant acceleration of 3x10^-3m/s^2. How long does it take to catch up to the bunny? I did this...
  42. H

    Kinetic Motion

    If Icalculate the wood, do I do the following: v2^2=v1^2 + 2ad 100^2 -400^2 = 2(-750,000)d d=0.1m
  43. H

    Kinetic Motion

    I really hope so, because the sheet says "bullet".
  44. H

    Kinetic Motion

    a= -750,000m/s^2 F = 6000N Just to save time
  45. H

    Kinetic Motion

    A 8.0g bullet traveling at 400m/s passes through a heavy block of wood in 4.0x10^-4s, emerging with a velocity of 100m/s. Ignore the motion of the wood. 1) What is the force exerted by the block on the bullet? 2) What is the force exerted by tbe bullet on the block? 3) How thick is the...
  46. H

    Just a confirmation

    Yes, I used the quotient rule: y'= (1-x^2)(2x)-(-2x)(x^2) / (1-x^2) y'= 2x-2x^3+2x^3 / (1-x^2)
  47. H

    Just a confirmation

    I just wanted to make sure I differentiated this correctly before I started graphing it: y=x^2/1-x^2 y' = (2x)/(1-x^2)^2 y''=(2+6x^2)/(1-x^2)^3
  48. H

    Okay, a stupid question about curve sketching

    That was a typo on my part (thank you for noticing it!) So there are no minimums in this case? Becaue when I try to calculate it, the 3 critical numbers I get are 2,-2, and 0. But if I sub in 2 or -2, I get 6, which doesn't seem right...
  49. H

    Okay, a stupid question about curve sketching

    err...it should be maximum, right?
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