Recent content by Roodles01

  1. Roodles01

    Density of bar submerged in water

    Homework Statement A bar suspended in air weighs 1.75 N The same bar weigs only 1.4 N when suspended in water. Calculate; a. upthrust b. density of the bar Homework Equations D = m/v F = m*a The Attempt at a Solution a[/B]. Upthrust is 1.75 N - 1.4 N = 0.35 N b. Assuming density of water...
  2. Roodles01

    What is a Dichromatic Prism and How Does it Work?

    I found what was called a "dichromatic prism" on ebay and bought it. It is a cube and although described as "not perfect" it splits light extremely well and is quite a cool object to show those in my staff room. I understand that dichroic is different but not sure how. Question is, how does it...
  3. Roodles01

    How Do You Calculate Average Charge Density in a Cylinder?

    ∫s ρ(r) dV = Q ∫ Cr2 * 4πr2 dr = 4Cπ ∫ r4 dr so Q = 4CπR5 / 5
  4. Roodles01

    How Do You Calculate Average Charge Density in a Cylinder?

    ∫ Cr2 dr C ∫ r2 dr (0 < l < L) CL3/3
  5. Roodles01

    How Do You Calculate Average Charge Density in a Cylinder?

    Homework Statement A cylinder of radius a and length l has charge distribution ρ=Cr2 where C is a constant and r is radial distance in cylindrical coordinates. Derive an expression for the average charge density within the cylinder. Homework Equations Well, charge density given is within the...
  6. Roodles01

    Fluid Statics - net upward force

    I have looked at the question and unscrewed the bits of paper I attempted my answers on and the h0 seems to be a complete typo, it all says just plain h. I will try to work through with that in mind, as you say.
  7. Roodles01

    Fluid Statics - net upward force

    Homework Statement Find magnitude of net upward force on a cube in terms of l, ρ (rho), g and h. then show that h = m/ρl2 A solid cube, mass m, side length l, is placed in a liquid of uniform density, ρ(rho), at a depth h0 below the surface of the liquid, which is open to the air. The upper...
  8. Roodles01

    Fluid Force on a Cube at Depth h0: Calculating Pressure and Magnitude of Force

    Homework Statement A solid cube, mass m, side length l, is placed in a liquid of uniform density, ρ(rho), at a depth h0 below the surface of the liquid, which is open to the air. The upper and lower faces of the cube are horizontal. Find the magnitude of force, Fs, exerted on each vertical...
  9. Roodles01

    Renewed career in science for age 50+ (UK)

    Having been a junior design engineer 15 years ago and moved out of that field I am looking to get back into a science based career. I am taking a "Natural Science" degree with a maths/physics bias (lots of that) and can't seem to get any sensible job before I get this in place. I used to use...
  10. Roodles01

    Relationship between elements and speed of light

    I recently watched a documentary presented by Professor Brian Cox called Human Universe. In it he was wondering how much leeway he would have, if he was "the creator of our universe", to alter the physical constants. He then went on to say that if he altered the speed of light one way then...
  11. Roodles01

    Partial differential - difference of opinion

    oops sorry. Just me being lazy
  12. Roodles01

    Partial differential - difference of opinion

    I have a difference of opinion with 2 calculation engines. equation to solve is; d/dx (a(x^2 +y) Wolframalpha of course is a very trusted source but I also use symbolab. Here is a screenshot of the differential I want from both sites and associated answers. . . . and the wolfram solution...
  13. Roodles01

    Free surface charge density (not bound density)

    Sorry, I should have said. D1 ┴ is the electric displacement in media 1 perpendicular to a boundary with a different media D2 ┴ is the electric displacement in media 1 perpendicular to a boundary with a different media They form the boundary condition could have been D1 = D2. and P is the...
  14. Roodles01

    Still struggling with physics, but trying, trying.

    Still struggling with physics, but trying, trying.
  15. Roodles01

    Free surface charge density (not bound density)

    Homework Statement a parallel plate capacitor has 2 plates separated by a dielectric of rel. permittivity 5.0 are separated by 0.20mm and have area of 5.0 cm2. Potential difference between the plates is 500V. I need to be able to calculate the free surface charge density...
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