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  1. B

    Shear Modulus of jiggling jello

    Thanks! I guess I was seeing 'jiggling' as more lateral movement.
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    Shear Modulus of jiggling jello

    Homework Statement A student bumps into a tray of jello. The lime jello is jiggling side to side faster than the orange jello. Both jellos have the same spatial dimensions. Which statement is true? Answer: Lime jello has a higher shear modulus than orange jello Homework Equations...
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    DNA waves and water

    "DNA waves and water" Hello all, I've tried to keep in touch with the physics world in my life beyond academics and I came across this paper: http://arxiv.org/PS_cache/arxiv/pdf/1012/1012.5166v1.pdf On one hand I think "this guy is a Nobel prize winner" and on the other hand I am...
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    Kirchhoff's circuit laws

    Blast from the past! I have since moved past physics and on to medicine so things worked out well enough I suppose.
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    Archived Series RLC circuits

    Homework Statement A series RLC circuit has a 0.19 mF capacitor, a 16 mH inductor, and a 10.0 resistor, and is connected to an ac source with amplitude 9.0 V and frequency 60 Hz. (a) Calculate the voltage amplitudes VL, VC, VR, and the phase angle phi . VL = V VC = V VR = V...
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    Kirchoff's Laws

    The junction rule is used here and you applied it correctly. Start at the positive end of the battery (the longer bar) of the 8v source. The perimeter loop should give you: 8v-110I1-50I3-50I1 The left hand loop gave me: 4v-40I2-51I3. Remember when you cross a resistor in the direction...
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    Kirchhoff's circuit laws

    Homework Statement http://img207.imageshack.us/img207/1685/p1854altco4.gif [Broken] Find the unknown emf and the unknown currents in the circuit below, in which R = 3.48 . Take the positive direction for current flow in each branch to be upwards. EMF = V left branch= A right branch=...
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    Dielectric help

    self-solved it. 180cm2 is .018m2, not .180m2 as I have recorded.
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    Dielectric help

    [SOLVED]Dielectric help Homework Statement To make a parallel plate capacitor, you have available two flat plates of aluminum (area = 180 cm2), a sheet of paper (thickness = 0.10 mm, k= 3.5), a sheet of glass (thickness = 2.0 mm, . k= 7.0), and a slab of paraffin (thickness = 10.0 mm, k=...
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    Electric Fields.

    Thank you, Leong.
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    Electric Fields.

    That answer was accepted. Thank you. If you have a minute, would you mind telling me how you came up with that?
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    Electric Fields.

    Tried that earlier and it did not seem to work.
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    Electric Fields.

    Thanks for the reply. I took 2(9e9*8e-10)/1.7^2 and came up with 4.98 which did not seem to work.
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    Electric Fields.

    Homework Statement Two equal charges (Q = +0.80 nC) are situated at the diagonal corners A and B of a square of side x = 1.2 m as shown in the diagram. What is the magnitude of the electric field at point D? Homework Equations E=kQ/r^2 The Attempt at a Solution First I converted...
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    Harmonic motion

    I got it. I needed to multiply out 6*pi to get its numerical value 18.85 and enclose the argument of the cosine function in parenthesis. 11cos(18.85t) worked.
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    Kinetic energy of moving automobile

    Your reasoning is correct. I wasn't understanding you at first.
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    Kinetic energy of moving automobile

    Keep in mind the equation for kinetic energy: K=1/2mv^2
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    Dropping a cylinder

    This is not too disimilar from a problem I did a little while ago: https://www.physicsforums.com/showthread.php?t=195028
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    Harmonic motion

    Homework Statement A 171 g object on a spring oscillates left to right on a frictionless surface with a frequency of 3.00 Hz and an amplitude of 11.0 cm. (a) What is the spring constant? N/m (b) If the object starts from rest at x = 11.0 cm at t = 0 and the equilibrium point...
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    Youngs modulus stress/strain.

    Thanks for your help.
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    Youngs modulus stress/strain.

    Homework Statement The figures below shows the forces acting on a tibia (shinbone, the long vertical bone in the figure) when a person stands on the ball of one foot. As shown, the force of the tibia on the ankle joint for a person (of weight 750 N) standing this way is 2800 N. The ankle...
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    [difficult] bernoulli's equation

    Homework Statement In an aortic aneurysm, a bulge forms where the walls of the aorta are weakened. If blood flowing through the aorta (radius 1.1 cm) enters an aneurysm with a radius of 3.1 cm, how much on average is the blood pressure higher inside the aneurysm than the pressure in the...
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    Acceleration of hollow sphere rolling down table.

    I solved it: 9.8sin(35)/(1+2/3) I am still not sure why it worked out that way. Any kind soul care to help me understand this a little better?
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    Acceleration of hollow sphere rolling down table.

    Thanks for the help. I am still a bit murky on this. I know torque=moment of inertia * radial acceleration. I need to find radial acceleration. How can I solve without knowing the torque or the mass of the object? How can I set up the problem in such a way to cancel the mass?
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    Acceleration of hollow sphere rolling down table.

    Homework Statement A hollow spherical shell is rolling without slipping or sliding down a board that is tilted at an angle of 35.0° with respect to the horizontal. What is its acceleration? Homework Equations I=2/3mr^2 if an object rolls without slipping or sliding: v = rw...
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    Linear and angular acceleration of a falling cylinder? [long]

    You're right about my algebra being bad. So now I cannot see how mass would be solvable. If that is the case I won't get a real numerical answer. Is that normal for these types of problems?
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    Linear and angular acceleration of a falling cylinder? [long]

    I came out with the same answers (once I knew what to do) so in real numbers a=2(9.81)/3=6.54 T=(1/6)mg=(1/6)(1/2)=1/12N Is this beast finally slain?
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    Linear and angular acceleration of a falling cylinder? [long]

    I blundered on my algebra as well. I should have: mg-2T=mr*alpha T=1/4mr*alpha mg-2(1/4)mr*alpha=mr*alpha cancelling the mr*alpha leaves me: mg=1/2 9.81m=1/2 m=.05kg
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    Linear and angular acceleration of a falling cylinder? [long]

    Solving for T in equation 2 gives me: T=mr*alpha Putting that into the equation derived from plugging (3) into (1) mg-2mr*alpha=mr*alpha that leaves me with mg=3 or m9.81=3 or .31kg Am I on the right track? The problem asks for linear acceleration of the cylinder as well as tension...
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