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    Thermo Heat Exchanger Problem

    Homework Statement I'm given three temperatures and four pressures for a heat exchanger. I am also given the mass flow rate, which is the same for both the inlets and outlets. There is no heat transfer between the heat exchanger and the surroundings. My task is to find the fourth...
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    FBD Help (Actual and Effective Loads)

    1. Homework Statement Obtain the pin-forces on the vertical bar BDE at the instant shown. Supply and document any additional information that my be necessary in order for this problem to have a tractable solution. 2. Homework Equations Newton's motion equations. [I'm just trying to...
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    Elementary Dynamics Problem (FBD Help)

    Homework Statement Obtain the pin-forces on the vertical bar BDE at the instant shown. Supply and document any additional information that my be necessary in order for this problem to have a tractable solution. (This is number 3 in the attached pdf file.) Homework Equations Newton's...
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    Interference from Thin Films

    Ok, I got the answer, but I want to make sure. Is it x_n_ = x/n_2_ where x_n_ is the wavelength in the oil and x is the wavelength in air? n_2_ is the index of refraction of the oil or glass correct? Thanks, by the way.
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    Interference from Thin Films

    Homework Statement Light of wavelength x, in air, is incident in air on a film of oil with index of refraction n_oil = 1.45. The film of oil has thickness L, and is spread on glass with an index of refraction n_glass = 1.50. The wavelength of the light in oil will be _____ than the wavelength...
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    Multiple FBD Dynamics Problem

    Homework Statement The 4-kg uniform rod ABD is attached to the crank BC and is fitted with a small wheel that can roll without friction along a vertical slot. Knowing that at the instant shown crank BC rotates with an angular velocity of 6 rad/s clockwise and an angular acceleration of 15...
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    Linear and anular momentum of a hydrogen electron

    Ok, I found the answer. Linear momentum 4.9821*10^-25 kg * m/s Angular momentum is 4.2182*10^-34 J*s There are also three other parts to the question: Find its kinetic energy, potential energy and total energy. (Use eV) I found its kinetic energy (.850625eV), but I can't find its potential...
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    Linear and anular momentum of a hydrogen electron

    Homework Statement A hydrogen is in the excited state of n=4. Using the Bohr theory of the atom, find the radius of the orbit. Find the linear momentum of the electron. (kg*m/s) Find the angular momentum of the electron. (J*s) Homework Equations r = a*n^2 ??? maybe L =...
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    Finding the distance an object will travel

    It's not really a problem, I'm doing an experiment where I hit an object with a hammer to see how far it travels. I have to determine whether the mass of the object affects how far it travels. Clearly it does, but I need some kind of relationship to prove it.
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    Finding the distance an object will travel

    Ok, the force acted on the body for an instant; it struck the object, and the object started moving. It was similar to a hockey stick hitting a puck.
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    Finding the distance an object will travel

    what is "e" in the equation a = -ve? Oh, also, I only know the force striking the object, I don't know the initial velocity.
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    Finding the distance an object will travel

    Shooting star, if I use the formula for constant acceleration, then I will end up with this: (V^2-V_0^2)/(2*a) = \Delta x If I use this equation with no acceleration, then I won't be able to get a distance because you can't divide by zero. Or, is the acceleration not zero?
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    Finding the distance an object will travel

    Hi. I have a question about finding the distance an object will travel along a horizontal surface. If I have a force striking an object directly in the horizontal direction, how would I go about finding how far it will travel? I already have found the frictional force acting on the object...
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    Coefficient of Friction?

    well, i don't want to round yet because i need that to do calculations. jeez
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    Coefficient of Friction?

    .35088
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    Coefficient of Friction?

    Thanks a lot guys. I did it by using the incline idea.
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    Coefficient of Friction?

    I don't have a spring scale, but do you have a suggestion on where to look for an alternate method? Thanks.
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    Coefficient of Friction?

    I've searched for this on google, but haven't found anything; does anyone know where to find the coefficient of friction between paper and plexiglass?
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    Finding Work Done by Friction

    Alright. Thanks a lot for the help!
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    Finding Work Done by Friction

    Yes, it does say that she pulls a rope 48 degrees above the floor, but I'm not given that force, I'm given the horizontal component, which shows 567N. I attached a picture, but maybe it isn't working. I found the force along the rope to be about 847N, but that is not horizontal.
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    Finding Work Done by Friction

    But that's what it says in the problem. "Sally applies a horizontal force of 567 N..." Ah, so I would do -567N*34.1m? The work done by friction would be -19334.7J then?
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    Finding Work Done by Friction

    So, the crate can be moving, but have 0 force acting on it? And if this is true, then is -567N correct?
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    Finding Work Done by Friction

    The opposite direction. That leads me to believe that the force of friction is -567 N, but that doesn't make sense to me because if the forces are opposite and equal, then the crate shouldn't be moving.
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    Finding Work Done by Friction

    The horizontal force on the crate is 567 N. The crate is not accelerating. The acceleration equals 0. Every sample problem in my book gives me the coefficient of friction. I really have no idea what to do. Maybe I do 567N/(9.8m/s^2), but that doesn't give me Joules.
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    Finding Work Done by Friction

    The Force of kinetic friction. But, I can't get that value without the coefficient.
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    Finding Work Done by Friction

    That's something that I thought of too when I was working on the problem, but that makes me think that the answer is 0. But, I know that's not right. The only equation I know that gives the work done by friction is Wfk = -fk*d.
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    Finding Work Done by Friction

    The last part of this problem has been bothering me. I don't understand how the work done by friction can be found if you are not given the coefficient of friction. Can anyone help me with this? There is a picture attached. Homework Statement Sally applies a horizontal force of 567N with a...
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    Vector Problem-Direction and Magnitude

    I have to use the angles to figure out which direction the resultant force is pointing after F_1 and F_2 are added, but I don't know how.
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