Recent content by Bri

  1. B

    Light again

    A ray of light strikes a flat block of glass (n=1.5) of thickness 2.0 cm at an angle of 30 degrees with the normal. Find the distance the light is shifted. I found the angle of refraction to be 19.471 degrees. I figured I could find the horizontal distance travelled by rays going through at...
  2. B

    Light and refraction in water

    I've tried it that way, I wasn't able to get anywhere with it.
  3. B

    Light and refraction in water

    Could someone tell me if I did this right? A narrow beam of sodium yellow light, with wavelength 589 nm in vacuum, is incident from air onto a smooth water surface at an angle of incidence of 35.0 degrees. Determine the angle of refraction and the wavelength of the light in water. I did...
  4. B

    Determine the final temperature of the mixture homework

    A combination of 0.250 kg of water at 20*C, 0.400 kg of aluminum at 26.0*C, and 0.100 kg of copper at 100*C is mixed in an insulated container and allowed to come to thermal equilibrium. Ignore any energy transfer to or from the container and determine the final temperature of the mixture. I...
  5. B

    What is the distance between the cliffs?

    A cowboy stands on horizontal ground between two parallel vertical cliffs. He is not midway between the cliffs. He fires a shot and heras its echoes. The second echo arrives 1.92 s after the first and 1.47 s before the third. Consider only the sound traveling parallel to the ground and...
  6. B

    Simple Harmonic Motion of a horizontal spring

    A 1.00-kg object is attached to a horizontal spring. The spring is initially stretched by 0.100 m, and the object is released from rest there. It proceeds to move without friction. The next time the speed of the object is zero is 0.500 s later. What is the maximum speed of the object? I...
  7. B

    Simple Harmonic Motion of a car's tires

    While riding behind a car traveling at 3.00 m/s, you notice that one of the car's tires has a small hemispherical bump on it's rim. If the radii of the car's tires are .300 m, what is the bump's period of oscillation? Can anyone tell me where to start with this? I'm actually not even sure...
  8. B

    Calculation of Moments of Inertia

    First of all, thanks to everyone for your input. I can do integration, but that equation there doesn't really make any sense to me... What is the V? Is it supposed to be a definite integral from V to... something? Other than the V thing, wouldn't it be r^2 \rho V? (r and \rho are...
  9. B

    Calculation of Moments of Inertia

    A uniform thin solid door has height 2.20 m, width .870 m, and mass 23.0 kg. Find its moment of inertia for rotation on its hinges. Is any piece of data unnecessary? So far, I don't understand how to calculate moments of inertia for things like this at all. I can do a system of particles...
  10. B

    Two-Dimensional Collisions

    Woohoo!! I got it now... Had to set the momentum to 0, not 20. Setting one of their velocities to negative because of their opposite direction slipped past me. Thanks so much for all the help!
  11. B

    Two-Dimensional Collisions

    Ok, so I used: m(b) = 1.2m(g) v(bi) = 25/3 m/s v(gi) = 10 m/s m(b)v(bi) + m(g)v(gi) = m(b)v(bf) + m(g)v(gf) 1.2m(g)v(bi) + m(g)v(gi) = 1.2m(g)v(bf) + m(g)v(gf) 1.2v(bi) + v(gi) = 1.2v(bf) + v(gf) 20 = 1.2v(bf) + v(gf) .5m(b)v(bi)^2 + .5m(g)v(gi)^2 = m(b)v(bf)^2 + m(g)v(gf)^2 275/3...
  12. B

    Two-Dimensional Collisions

    Do I need conservation of momentum to solve for the final speeds? Should I be separating it into two equations for KE and Momentum, one for in the x direction and one for in the y direction? And wouldn't I end up with 4 equations then? What would I do with them? I used momentum to find the...
  13. B

    Two-Dimensional Collisions

    The mass of the blue puck in the figure is 20.0% greater than the mass of the green one. Before colliding the, the pucks approach each other with momenta of equal magnitudes and opposite directions, and the green puck has an initial speed of 10.0 m/s. Find the speeds of the pucks after the...
  14. B

    Two-Dimensional Collisions

    Two shuffleboard disks of equal mass, one orange and the other yellow, are involved in an elastic, glancing collision. The yellow disk is initially at rest and is struck by the orange disk moving with a speed of 5.00 m/s. After the collision, the orange disk moves along a direction that makes...
  15. B

    Changes in Mechanical Energy for Nonconservative Forces

    Oh, ok! Thanks so much for the help!
Top