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  1. W

    How do you calculate the energy required via torque when...

    The "load" is just my way of saying the force. I understand the integral, I just wasn't sure if it was as easy as dropping in the FrSin[x] into the integral, but I guess it is. Thank you.
  2. W

    How do you calculate the energy required via torque when...

    Let's say you have a lever arm connected to a load at the end. But the load is attached to a hinge, so no matter where the lever arm is, the load is always pointing down. I know that Energy = [integral] tau d_phi, but does that only work if the angle b/w arm and load is constant? What if the...
  3. W

    How does the Beer Lambert law work at non-normal incidences?

    Okay, so I calculated Rp+Rs / 2, and I got 93% reflectivity, but that doesn't take into account the thickness of the film. I think it's more appropriate as a way to model a thick film where practically nothing makes it through the aluminum film. EDIT: Or is it just impossible, regardless of...
  4. W

    How does the Beer Lambert law work at non-normal incidences?

    Thanks Dr Du. Since my light source is going to be unpolarized, the total reflectance is going to be (Rs+Rp)/2. Since both Rs and Rp are dependent on n2, would I just use the real index of refraction to calculate the amount reflected, and then when calculating what is attenuated, use the...
  5. W

    How does the Beer Lambert law work at non-normal incidences?

    I want to calculate the intensity of a transmitted wave in a medium, but not at normal incidence. I want to consider the case of 45 degrees. What proportion of the intensity of the wave is lost by reflection? Specifically I am looking at a the reflection off of a thin film of aluminum...
  6. W

    Epicyclic motion and precession

    Imagine I am standing but not moving forward/backward, but I am rotating my body about my own axis. Now imagine if I moved in a circular path as I was spinning on my own axis. Is this considered to be precessing (assuming the axis of rotations are always in the z direction)? My friend...
  7. W

    Acceleration and thrust of a rocket

    I calculated velocity of the rocket by integrating the function for acceleration w.r.t time. Isn't that how thrust is defined? Yes, I am aware. In my original post, I specified that v was for gas ejection. Although I should have specified that the velocity in the graph is the velocity of...
  8. W

    Acceleration and thrust of a rocket

    Hey guys, I want to know if I have an equation on thrust correct. I figured whats the acceleration as a function of time. You have the upward thrust = dm/dt v, assuming the mass flow rate and the gas ejection rate is constant and the downward force = -m(t) g, where m=m(t) since it's...
  9. W

    How does refrigeration work?

    piVi / pfVf = nRTi / nRTf the n's and R's cancel out: piVi / pfVf = Ti / Tf now if the compressor can compress some special refrigerant gas to, lets say, Vf=\frac{1}{3}Vi and pf=2pi, then piVi / 2pi\frac{1}{3}Vi = Ti / Tf Then the pi's and Vi's cancel. Simplify to get...
  10. W

    How does refrigeration work?

    unless i made a typo in my original post, I don't believe I have said anything erroneous. If you lower the volume, i.e. squeeze the gas into a smaller spot, the pressure increases. If you increase the volume, i.e. give the gas molecules more room to spread out, the pressure decreases...
  11. W

    How does refrigeration work?

    Does this apply to every gas? When a gas expands, its pressure decreases. And like I said, is it possible for the increase in V to be equal to the decrease in p, resulting in no net change in T?
  12. W

    How does refrigeration work?

    I know I can easily look this up on Wikipedia, but I chose to use my intuition on this one ;) Tell me if my intuition based approach is correct: You have a compressor which takes a refrigerant gas such as Freon and compresses/decompresses it. I'm imagining it works something like a piston in...
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