• Tough geometry problem?

    I'm hoping that someone can look at this and have an "ah ha" moment and an elegant solution, but I'm making a simple sliding panel/door, the cross section is shown in the picture. What is the greatest height (L in the picture) that the door can have such that it can be removed from the frame?
    I'm hoping that someone can look at this and have an "ah ha" moment and an elegant solution, but I'm making a simple sliding panel/door, the cross section is shown in the picture. What is the greatest height (L in the picture) that the door can have such that it can be removed from the frame?
    2 answers · Mathematics · 5 months ago
  • Can a gravity driven machine be built such that it accelerates an object faster than freefall?

    It seems counterintuitive, but so are DDWFTTW carts. It may be possible, since if speed is increased, so too is the power provided by gravity Fds/dt. Imagine this device vertically constrained: https://www.youtube.com/watch?v=k-trDF8Yldc with a very heavy ruler. The cart should shoot down faster than g right? It seems like there must be some... show more
    It seems counterintuitive, but so are DDWFTTW carts. It may be possible, since if speed is increased, so too is the power provided by gravity Fds/dt. Imagine this device vertically constrained: https://www.youtube.com/watch?v=k-trDF8Y... with a very heavy ruler. The cart should shoot down faster than g right? It seems like there must be some constraint, e.g. that the center of mass can't fall faster than freefall, but I'm not certain.
    6 answers · Physics · 5 months ago
  • Is this is a Poisson process?

    A Special Flood Hazard Area at high risk for flooding has a 1 in 4 chance of flooding during a 30-year mortgage. What is the probability of flooding for during a general duration, t, say 5 years or 70 years? Hopefully someone more familiar with probability can help me out. Thanks.
    A Special Flood Hazard Area at high risk for flooding has a 1 in 4 chance of flooding during a 30-year mortgage. What is the probability of flooding for during a general duration, t, say 5 years or 70 years? Hopefully someone more familiar with probability can help me out. Thanks.
    2 answers · Mathematics · 5 months ago
  • Ryzen processor users?

    could you go into device manager/processors/ryzen . . ./properties/driver details and tell me what driver file is being used? Mine is listing a microsoft driver from 2009, none of the AMD packages seem to install over this driver, which seems a little odd.
    could you go into device manager/processors/ryzen . . ./properties/driver details and tell me what driver file is being used? Mine is listing a microsoft driver from 2009, none of the AMD packages seem to install over this driver, which seems a little odd.
    1 answer · Desktops · 7 months ago
  • Attn: math buffs, probability?

    1 answer · Mathematics · 10 months ago
  • An actual, practical problem?

    I recently acquired a new truck, problem is, most all new trucks have ridiculously short beds, and one of the things I need to do is haul rough and dimensional lumber. If I have plank, length L, is it more stable to place it in the bed with the tailgate up (with the rear of the plank in the air), or to leave the tailgate down? The bed of the truck... show more
    I recently acquired a new truck, problem is, most all new trucks have ridiculously short beds, and one of the things I need to do is haul rough and dimensional lumber. If I have plank, length L, is it more stable to place it in the bed with the tailgate up (with the rear of the plank in the air), or to leave the tailgate down? The bed of the truck is 61" and the tailgate is 21". With the tailgate down, the board is more prone to sliding out upon acceleration, and snapping in half on large bumps. With the tailgate up, there will be a wind load trying to tilt the board out of the bed. Any suggestions are welcome, although I don't have any space for a trailer.
    2 answers · Physics · 12 months ago
  • Why is the assumption of nothingness prior to existence so natural?

    We ask, "Why is there something?", as if the existence of nothingness were a possibility--when the whole time, "Nothing" is "that which does not exist".
    We ask, "Why is there something?", as if the existence of nothingness were a possibility--when the whole time, "Nothing" is "that which does not exist".
    20 answers · Philosophy · 2 years ago
  • Help with nonlinear differential equation?

    From the simple problem of picking up a chain subject to gravity with a constant force, the equation of motion looks like: (a - bL) = L(L''), where a and b are constants. Is this solvable for L(t)?
    From the simple problem of picking up a chain subject to gravity with a constant force, the equation of motion looks like: (a - bL) = L(L''), where a and b are constants. Is this solvable for L(t)?
    1 answer · Mathematics · 3 years ago
  • A simple, perhaps unsolvable, question: lifting a chain?

    This was asked on here and it has me stumped: Imagine a long chain, linear mass density ρ, that you pick up with constant force F. How many meters of chain are off the ground in 5 seconds? I started with: F - gρL = ρL(dv/dt) where L is the length of suspended chain. Multiplied by 1/v = dt/dL to get (F/L - ρg)dL = ρvdv and integrated... show more
    This was asked on here and it has me stumped: Imagine a long chain, linear mass density ρ, that you pick up with constant force F. How many meters of chain are off the ground in 5 seconds? I started with: F - gρL = ρL(dv/dt) where L is the length of suspended chain. Multiplied by 1/v = dt/dL to get (F/L - ρg)dL = ρvdv and integrated to Fln(L/L₀) - ρg(L - L₀) = ρ/2(v^2 - v₀^2) Problem is, this doesn't integrate easily to find L in terms of t. Moreover, it has some nasty behavior that I hoped integrating would smooth out. For instance, it blows up initially, if there is no initial chain length. This is due to an infinite acceleration at the beginning, since the suspended mass is 0. Help?
    1 answer · Physics · 3 years ago
  • Tree with odd fruit/nut identification?

    The fruit/nuts seem the most distinctive feature on this one. The second is the relatively smooth gray bark. This is in USDA zone 6/7. I've had no luck in identifying it. Thanks. https://onedrive.live.com/redir?resid=38... https://onedrive.live.com/redir?resid=38...
    The fruit/nuts seem the most distinctive feature on this one. The second is the relatively smooth gray bark. This is in USDA zone 6/7. I've had no luck in identifying it. Thanks. https://onedrive.live.com/redir?resid=38... https://onedrive.live.com/redir?resid=38...
    1 answer · Botany · 3 years ago
  • Shrub/small tree identification?

    The fruit/nuts seem the most distinctive feature on this one. The second is the relatively smooth gray bark. This is in USDA zone 6/7. I've had no luck in identifying it. Thanks. https://onedrive.live.com/redir?resid=38... https://onedrive.live.com/redir?resid=38...
    The fruit/nuts seem the most distinctive feature on this one. The second is the relatively smooth gray bark. This is in USDA zone 6/7. I've had no luck in identifying it. Thanks. https://onedrive.live.com/redir?resid=38... https://onedrive.live.com/redir?resid=38...
    2 answers · Garden & Landscape · 3 years ago
  • MATLAB Vectorization help?

    I have the indexes of an array in an array. While that may sound confusing, all I want to do is take the array [ 1 2 .004 2 3 .02 3 4 .7 2 4 .01 4 5 .006] and create the array [0 .004 0 0 0 0 0 .02 0 0 0 0 0 .7 0 0 0 0 0 .006] elegantly in MATLAB without for loops.
    I have the indexes of an array in an array. While that may sound confusing, all I want to do is take the array [ 1 2 .004 2 3 .02 3 4 .7 2 4 .01 4 5 .006] and create the array [0 .004 0 0 0 0 0 .02 0 0 0 0 0 .7 0 0 0 0 0 .006] elegantly in MATLAB without for loops.
    2 answers · Engineering · 5 years ago
  • Winding a toroid for Tesla's egg?

    Tesla's original exhibit for the 1893 Chicago World's Fair used 2 phase power on 4 coils wound on a toroid in a bucking configuration like so: http://www.youtube.com/watch?v=Ec4u4BfS4tE&lr=1 The bucking configuration causes the magnetic flux to leave the metal core and fill the airgap, similar to a deflection yoke in a CRT, which in... show more
    Tesla's original exhibit for the 1893 Chicago World's Fair used 2 phase power on 4 coils wound on a toroid in a bucking configuration like so: http://www.youtube.com/watch?v=Ec4u4BfS4... The bucking configuration causes the magnetic flux to leave the metal core and fill the airgap, similar to a deflection yoke in a CRT, which in turn causes the egg to spin in a way similar to the rotor in an induction motor. My question is this: with modern know-how, how would you create such a device (say using 3 phase power), and more to the point, how best to efficiently generate a main field inside the airgap (or better, slightly above it) of a coil and minimize stray field? All practical (use a the stator from a three-phase motor or 3 pairs of Helmholtz coils with 3 phase power) and crackpot (use Rodin and starship coils) ideas are appreciated.
    2 answers · Physics · 5 years ago
  • When you are kind to a distrustful person?

    they will think that you are trying to get something out of them. How can one show kindness to a distrustful person?
    they will think that you are trying to get something out of them. How can one show kindness to a distrustful person?
    1 answer · Religion & Spirituality · 5 years ago
  • The sum of equally spaced chords?

    How much wire does it take to make a grid by wrapping wire around pegs installed along the circumference of a circle (spaced equally along a singe axis)?. Here's a crude representation of half of the circle and what I'm talking... show more
    How much wire does it take to make a grid by wrapping wire around pegs installed along the circumference of a circle (spaced equally along a singe axis)?. Here's a crude representation of half of the circle and what I'm talking about: .............................. ..............................| ..........................|...| ......................|...|...| ...................|..|...|...| ...................|..|...|...| ......................|...|...| ..........................|...| ..............................| I found the answer in terms of a hideous sum but I'm hoping someone can find a closed form for it.
    1 answer · Mathematics · 6 years ago
  • Does Led Zeppelin make Tolkien cooler by referencing The Lord of the Rings?

    Or does referencing The Lord of the Rings make Led Zeppelin cooler?
    Or does referencing The Lord of the Rings make Led Zeppelin cooler?
    5 answers · Philosophy · 7 years ago