Recent content by HoodedFreak

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    Mass falling and pulling others on a rough surface

    I believe that should give you a = g(1 - 3μ)/4 Then you need to ensure that a is positive, g and 1/4 are positive constants so you have the restriction that: 1-3μ ≥ 0
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    Elasticity of a Wire spinning in a circle

    I was rushing everything and made a lot of mistakes. I corrected those mistakes since then and got the correct answer. Thanks for the help!
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    Elasticity of a Wire spinning in a circle

    The change in length should be Δl Using the two equations I had: T - 12g = 12*16π / (0.7 + Δl) and Y * Strain = Stress ⇒ 6.9*10^9 * Δl/0.7 = T/0.014 Solving for T from the first equation to get T = 12*16π / (0.7 + Δl) + 12g Plugging it into the second, to get 12*16π / (0.7 + Δl) + 12g =...
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    Elasticity of a Wire spinning in a circle

    Also, to harupex's point, should I ignore the elongation and just treat the radius of the circle as R = lo = 0.7m since it should be small in comparison to the length.
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    Elasticity of a Wire spinning in a circle

    Right, yeah, so that would be 69*10^9 then. Okay, so if I plug in 69*10^9 * Δl/lo = T/0.014, then T = 69*10^9*0.014 * Δl / 0.7 = 1380,000,000*Δl SO 1,380,000,000*Δl - 12g = 12*16π / (0.7 + Δl) (1,380,000,000*Δl - 12g) * (0.7 + Δl) = 603 And I solve this quadratic? It seems like I'm doing...
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    Marble Stack Equilibrium: Solving for Forces at Contact Points

    Right, okay, so the center of gravity in between the two balls should be at a horizontal distance of 1.5 from the corner, which is 0.5 from point B, so the torque due to grabity would be 0.5*0.15g, so in the end we have 0.075g + Fa = (√3 + 1)Fa, which gives me 0.075g = √3Fa, and in the end, We...
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    Elasticity of a Wire spinning in a circle

    Young's modulus for aluminum, according to google is 69 N/m^2
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    Elasticity of a Wire spinning in a circle

    Homework Statement A 12.0-kg mass, fastened to the end of an aluminum wire with an unstretched length of 0.70 m, is whirled in a vertical circle with a constant angular speed of 120 rev>min. The cross-sectional area of the wire is 0.014 cm2. Calculate the elongation of the wire when the mass is...
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    Marble Stack Equilibrium: Solving for Forces at Contact Points

    I see, that makes perfect sense thanks for the explanation. Okay, so now I form the triangle with horizontal 1 and hypotenuse 2, solving for the height gives me √(22 - 12 = √3. So a total vertical distance of √3 + 1. So the torque on the system from point C woould be Fc * (√3 + 1). So i get...
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    Marble Stack Equilibrium: Solving for Forces at Contact Points

    Why did you draw a straight line between the two centers, isn't it possible to have the two centers not lie on a line through both their radiuses, I'd draw what I mean, but paint won't allow me to, something along these lines
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    Marble Stack Equilibrium: Solving for Forces at Contact Points

    How do you know what the center to center distance is? Clearly the horizontal distance of the centers would be 1, but how do you know the distance from one center to another?
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    Marble Stack Equilibrium: Solving for Forces at Contact Points

    I see, okay. But why is it valid to treat them both as one system together since they are not attached to each other? Okay, so if I treat them as a system together, then the lever arm at point C would simply be the vertical distance to point C, but we aren't given how high above the bottom of...
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    Marble Stack Equilibrium: Solving for Forces at Contact Points

    My last message is complete I just forgot to put the period. Which two torques are zero about point B? And why are we looking for the lever arm of point C when point C is not in contact with the bottom left marble.
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    Marble Stack Equilibrium: Solving for Forces at Contact Points

    Okay, well if I look at the torque of the first marble about point A, we have the torque from the force of the wall at A being zero, then we have the torque of the Force B being 0.15*g*1, and the torque of the second marble acting on the first, which I don't know how to find
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