Search results

  1. U

    Effect of Strain Hardening on Yield Strength

    Homework Statement The strain hardening behavior of an annealed, low‐carbon steel is σ = 100,000ε0.2 If a bar of this material is initially cold worked 20%, followed by additional cold work of 30%, determine the probable yield strength of the final bar. Homework Equations σ=κεη...
  2. U

    FBDs and Tension

    Hah that makes things easy. I guess I was thinking back to statics where if I was assuming a member to be in tension, but my answer came out negative then I had assumed wrong and it was in compression. Thanks alot.
  3. U

    FBDs and Tension

    Homework Statement While working through problems I always have trouble determining the direction that tension acts in on objects in the system. In system B.) block A has a velocity of 4m/s to the right, with mu(k)=0.2, causing the mass B to fall, in class tension was assumed to be in the...
  4. U

    Simple Thermodynamics

    R = 8.314 / Molecular Weight of helium
  5. U

    Statics hw problem

    You can solve this using either the Relative Motion Method for mechanism analysis, or Instantaneous Centers of Rotation. I`m guessing you havent covered either of these in your course, I did a quick search and found this book if you want to read up on it...
  6. U

    Help On Moments

    If you want me to go through the whole problem let me know.. But the problem with your solution is with Force B. Under your moment column for this force you have 5.65 x 0 = 0. This is incorrect. The VERTICAL moment of force B IS ZERO! Since the hozitonal distance from Fb to the pivot is...
  7. U

    Heat Transfer question.

    I may be able to help a bit..I had a question simmilar to this, but I've handed it in. I made and used a spreadsheet to solve it, not calculus. With all of your given information, you can solve for the temperature of the fluid inside the pipe. (Is the thermal conductivity of the pipe...
  8. U

    Heat Transfer

    Homework Statement An electrical wire 1/8" in diameter is covered with insulation 3/32" thick. Six watss of electrical energy are dissipated as heat by the resistance of the wire per foot length. The heat is given up to the surrounding air at 60 degrees farneheit. Estimate the outside...
  9. U

    Shear force and bending moment diagrams

    It's been awhile since Ive done this but hopefully I can help a little. I can't read your SFD too well, but to solve for the bending moment at D.. Take moments from point A Ma = 0 kn . mm Mb = 0 + (Length x Width on your SFD) The bending moment at D will be Mc + (Bound area from...
  10. U

    Fluid mechanics involving stability

    i have a quick question about stability..sorry if im hijacking the thread.. If you are determining wether something will be stable or not, is it only dependant on wether the metacenter is above the center of gravity?
  11. U

    Fluid Mechanics - Distance to Centroid

    Homework Statement http://i284.photobucket.com/albums/ll12/uradnky/fluid.jpg I'm asked to solve for the force on the projected plane surface and show where it is acting. This problem seems pretty easy, but with the dimensions given I can't find Lc, so I cant find dc to begin it. Is...
  12. U

    Conservation of Energy - Roller Coaster

    Homework Statement A roller coaster car has a mass of 800kg. It is released from the top of the hill A and moves without friction down the track. Determine the minimum exit velocity vD at ground level so that the car travels around both the circular loops (Loop B - Radius= 10m, Loop C -...
  13. U

    Area under curve

    That was easy. Thanks.
  14. U

    Area under curve

    Homework Statement Find the area bound by y= x - 2\sqrt{x} and y=0 The Attempt at a Solution X intercept = 4 Y intercept = 0 Using verticle rectangles.. dA = ((Upper curve)-(Lower curve)) dx \int(dA = \int(0-(x-2\sqrt{x})) dx A= -(1/2X^2)-((2x^(3/2))/(2/3)) Evaluated from...
  15. U

    Applications of Integrals

    Homework Statement In coming to a stop the acceleration of a car is given as a= -4t. If it is traveling at 32m/s when the brakes are applied, how far does is travel while stopping? The Attempt at a Solution 1.) Integrate acceleration to find velocity as a function of time v=...
  16. U

    Calculus - Max/Min

    Yeah, with 1st derivative test right? I just figured that it would be ok to assume a maximum because thats what the question asked for, and solving for r only gave me one value.
  17. U

    Calculus - Max/Min

    Thanks for confirming it for me. Plugging .8 into the derivative gives me 0 so i guess i was right all along.
  18. U

    Calculus - Max/Min

    Homework Statement The electric power in Watts produced is given by p= 144r/(r+.8)^2 where r is the resistance in ohms. For what value of r is the power P a maximum? Homework Equations The Attempt at a Solution Using the quotient rule i found a derivative of.. dp/dt= 144(-r+.8)...
  19. U

    Related Rates height of rising water

    kjlhdfkljdshfkljnvckjnd pretty ugly mistake. I guess I haven't done quotient rule in awhile hah. I didn't pay any attention when you showed me how to do it with the quotient rule. Sorry for wasting your time bro, but thanks for all the help.
  20. U

    Related Rates height of rising water

    (dh/dt) = (160)(.8) = 128 ...this isn't the correct answer?
  21. U

    Related Rates height of rising water

    If I tried this using the quotient rule, would this be the correct way to go about it? (I know it isnt..) (dh/dt) = (160)(dv/dt)-(v)(0)
  22. U

    Related Rates height of rising water

    So since the denominator is a constant it isn't necessary to use the quotient rule?
  23. U

    Related Rates height of rising water

    Thanks for the help. One thing I don't understand though.. I rearrange V = LWH to solve for H. That gives me H = V/LW. Now when I take the derivate implicitly, wouldnt I need to use the quotient rule to get the derivative of V/LW? That is how I got LW(dv/dt) and not the correct answer of...
  24. U

    Related Rates height of rising water

    Homework Statement A rectangular swimming pool 16m x 10m is being filled at a rate of .8m^3/min. How fast is height of the water rising? Homework Equations V = LWH The Attempt at a Solution H = V/LW (dh/dt) = LW(dv/dt) (dh/dt) = (10)(16)(.8) This question looks so easy...
  25. U

    Volume rate problem

    It all looks good to me to. Except for when the radius is 24 I got 4608. Maybe you just had a typo there?
  26. U

    Statics - Method of Members

    That cleared things up alot thanks.. So member BC is the 2 force member because it only has the forces B and C acting on it? Member BC is in tension so it can only pull on the pins at B and C? Is this correct? Because of this, when I draw the FBD of member BC the reactions are only in the...
  27. U

    Statics - Method of Members

    Oh I didnt realize that it had to get approval before uploading. Here's a link to the truss.. http://i284.photobucket.com/albums/ll12/uradnky/truss.jpg Thanks again
  28. U

    Statics - Method of Members

    Thanks for the reply. I understand what you are saying but I have trouble applying it. Could you maybe explain to me, on the attached truss where the two force member is and how you came to that conclusion? I would really appreciate it.
  29. U

    Statics - Method of Members

    What is the easiest way to determine the two force member in a frame question? When I look at a frame and see the pinned connections, I automatically assume that there is a reaction in the x and y directions. How can I tell at which pin there is only one reaction, and what direction it is...
Top