Search results

  1. F

    Electric motor contest - suggestions?

    there is a contest to build an electric motor for which we can get some bonus points on the final in my E&M class. they give us a very limited kit and we can only use what comes in the kit which is a couple pieces of thick poster board, 6 feet of insulated wire, a couple paper clips, a couple...
  2. F

    Problems with file sharing programs

    I haven't been able to get any file sharing programs to work with my computers connection. I'm using a school connection - T1 I think. I've tried Limewire, Ares, and WinMX. I got WinMX to connect and search, but nothing would download - they all just said Waiting for network response and then...
  3. F

    Sodium Hydroxide and Plastic

    I have some crystallized sodium hydroxide drain cleaner that I want to use on my bathroom sink drain, but I just put in a plastic drain and the trap is plastic as well. The clog is past the trap, somewhere deeper. So will the NaOH be alright with the plastic? Not sure exactly what kind of...
  4. F

    Stargazing A telescope orbiting an outer planet?

    The idea popped into my head today of building an extreme telescope (larger than hubble) to orbit an outer planet such as Jupiter etc.. I'm thinking that with it being past the asteroid belt, we would be able to see farther and clearer than with the hubble. Is this an accurate assumption? The...
  5. F

    Stargazing What am I doing wrong? - Telescope Trouble

    I decided to dust off my old telescope to see what I could see. I was looking at the moon and messing around, but I could only get a sharp image with the eyepiece removed. Without the eyepiece, I can focus in a good image with my glasses on or off, but with it in it is only a blob of white...
  6. F

    Gravitational Potential Energy and force

    The gravitational potential energy (U) of an object, from some reference point - such as the surface of the earth, is defined as the amount of work required to move the object from the reference point to its position. The force of gravity is given by: F = -\frac{GMm}{r^2} where r is...
  7. F

    Torque - In Depth

    I have a few years of physics experience, and as I was thinking about a few things the other day, something about the concept of torque seemed a little weird to me. Simple Forces are easy to understand - gravity pulls down on an object, the ground pushes back up with an equal and opposite...
  8. F

    Energy required to keep air in a plasma state

    Say that you are continuously creating plasma with some sort of sparking device. How strong of an electrical field is required to keep this air in its ionized state, compared to the field needed to ionize it initially?
  9. F

    Simple Harmonic Motion - Period of a Pendulum

    We are talking about SHO in physics and the forumula for period T of a pendulum was introduced - T=2*pi*(L/g)^.5 where L is the length of the pendulum arm/string and g is acceleration due to gravity. the instructor also said this was an approximation that was only accurate for small angles...
  10. F

    Gravity, Kepler's Laws

    Use the following data to calculate the speed vp of comet Halley at perihelion. Comet Halley orbits the Sun with a period of 76 years and in 1986 had a distance of closest approach of 8.90×1010 m and an aphelion distance of 5.30×1012 m. I'm stumped so far on this one. I'm assuming the...
  11. F

    Angular Momentum - Precession

    Precession for me is one of the most confusing and interesting concepts in physics so far, I've thought about it alot and I still don't have it all figured out. Here's an interesting question: Consider a gyroscope that has the axle in a horizontal position and spinning so that the angular...
  12. F

    Conservation of Momentum (Linear and Angular)

    On a frictionless table, a glob of clay of mass 0.38 kg strikes a bar of mass 1.76 kg perpendicularly at a point 0.12 m from the center of the bar and sticks to it. If the bar is 0.66 m long and the clay is moving at 5.7 m/s before striking the bar, what is the final speed of the center of...
  13. F

    Angular Momentum/Rotation Problem

    A uniform billiard ball with radius R= 7.00 cm rests on a billiard table. At one moment, the ball received a hit from the horizontal direction. Hit point is h above the center of the ball. Then, the ball begins to move with a velocity V0= 15.0 m/s. The kinetic coeffient between table and the...
  14. F

    Conservation of momentum of a rocket

    The last stage of a rocket is traveling at a speed of 8000 m/s. This last stage is made up of two parts that are clamped together, namely, a rocket case with a mass of 330.00 kg and a payload capsule with a mass of 155.00 kg. When the clamp is released, a compressed spring causes the two parts...
  15. F

    Electric charge, creating plasma and keeping it apart

    if you have a device similar to a stun gun, with a spark continuously jumping across the 2 contact points. electric field has to rip electrons from the air moecules leaving positive ions - creating plasma. now imagine you have a negatively charged disc nearby the device which is covered in a...
  16. F

    Spatial dimensions above the 3rd

    what do spatial dimensions higher than the third dimension mean? what do they represent. any object can be described in 3 dimensions, how are higher dimensions possible? how can you even comprehend them?
  17. F

    Calculating values of trig functions

    How does a calculator approximate a trig function. For example, you punch in sin(37deg) and the calculator will give you 0.6018150232. how does it figure this out?
  18. F

    Conservation of energy

    consider 2 identical rockets, same mass and size, same engine which gives a constant thrust. the rockets are both moving upward. the thrust of the engine is equal to the weight of the rocket (assume the mass of the fuel lost is negligable). therefore the forces are balanced so if one of the...
  19. F

    Physics - work done by a spring

    A moving 4.90 kg block collides with a horizontal spring whose spring constant is 437 N/m. The block compresses the spring a maximum distance of 6.50 cm from its rest position. The coefficient of kinetic friction between the block and the horizontal surface is 0.190. What is the work done by...
  20. F

    The physics of putting a rocket into space

    If a rocket is launched into space in attemt to break orbit and continue into deep space, how do you determine when the rocket "breaks" the gravitational pull of the earth? Since gravity extends infinatly, how do you know when you are at a point where if you kill the engines, it will continue...
  21. F

    Concept of a gyroscope

    Consider the concept of a gyroscope. You tie a string to one end and attach the other end to the ceiling so only one end is supported, If you let go when it is not spinning, the obvious occurs - it falls from its horizontal position to a vertical position with the other end pointing towards the...
  22. F

    Linear transformations

    Im a second semester engineering student and im a few weeks into a linear algebra class. I understand most of it, but my teacher has to work to speak english so she doesn't explain things very well. We just started linear transformations and a few things seem unclear to me. Take a shear...