Recent content by JPKelly

  1. J

    Find Poisson's Ratio of Aluminum from Torsion and Tensile Tests

    Thank you so much! I actually discovered that shortly after I posted the thread. Thank you again. James
  2. J

    Find Poisson's Ratio of Aluminum from Torsion and Tensile Tests

    1. Torsion test showed aluminum to have shear modulus of 4.60x10^6psi. Under a tensile test, the same specimen showed a modulus of elasticity of 12.2x10^6psi. Find Poisson's Ratio. 2. Poisson's Ratio=lateral strain/axial strain 3. The ratio is a function of both strains. The...
  3. J

    Creating a 556 Timer from Two 555s - Possible?

    Is it possible to create a 556 timer from two 555 timers rather than just purchasing one 556? Thanks
  4. J

    How Do You Calculate Mass Flow Rate from a Rocket Motor Burn Graph?

    Cool, I'll have to try that method. I have actually been through Calculus I during my Freshmen year at college. But i never really understood the concept of it all. Teachers(in this area) spend not near enough time on application of Calculus and explaining concepts of it. It reached the...
  5. J

    How Do You Calculate Mass Flow Rate from a Rocket Motor Burn Graph?

    Well I suppose I don't even understand what I am asking. Ha. In calculus when you find the slope of one point on a line by taking the derivative i don't understand how that applies to rate of change. Im talking about finding the rate of change at a certain point on a non linear line. Say from...
  6. J

    How Do You Calculate Mass Flow Rate from a Rocket Motor Burn Graph?

    I have been reading a lot about rockets and how the mass flow rate is calculated. If i had a graph of the change in mass with respect to time of a rocket motor throughout its burn. How would i calculate the mass flow rate (change in mass at any given time t) ? Besides using density...
  7. J

    Help with Newtons 2nd applied to Rocketry

    This is a direct quote from nasa.gov. I understand everything up until the last equation. Can it not be written like F = mdot(v2-v1) ? Also, this equation F = d(mv)/dt is the same as this F = (m dot * V)e - (m dot * V)0 ? Or no? I understand Mass x Velocity is momentum and they want the...
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