Recent content by jjlandis

  1. J

    Simple Harmonic Motion

    I think I am confused about "phase angles" as well. Figure out how fast the bull is moving once it exceeds the acceleration of gravity? Does that mean I am still using the SHM veloctiy and acceleration equations?
  2. J

    Simple Harmonic Motion

    The equation assumes t = 0 and v(ox) = v(x). I figured the initial velocity would be the instant the rider left the bull. the angle is the phase angle, and without an x direction, I didn't think there would be any angle. and since amplitude and frequency were given, that left me only a V(ox)...
  3. J

    Simple Harmonic Motion

    Homework Statement While visiting friends at Cal State Chico, you pay a visit to the Crazy Horse Saloon. This fine establishment features a 200- kg mechanical bucking bull that has a mechanism that makes it move vertically in simple harmonic motion. Whether the “bull” has a rider or not, it...
  4. J

    Asteroid Radius problem

    PERFECT!!! I was under the impression you had to solve for the gravitational acceleration on the surface of the asteroid first. I kept getting to... G*2260*(4/3*pi)*r^2 = g*h but i would try to derive another equation to substitute for "r" to try and solve for "g". - If the the...
  5. J

    Asteroid Radius problem

    By taking density = Mass / Volume, and volume = (4/3)*pi*R^3, I can see relating mass to radius but that still leaves me with mass and radius unknown right? i'm still having trouble and not making very much headway. The substitution still leaves: rho = mass / ((4*pi*R^3) / ) ....and this...
  6. J

    Asteroid Radius problem

    Right, the volume of the sphere compared to the area of a circle. Every equation I come up with, I end up with 2 unknown variable. Between gravity of the asteroid, R, and mass of the asteroid.
  7. J

    Asteroid Radius problem

    I solved for the escape velocity and the radius and get 11.4 km. The correct answer is 3.63 km. I assume the escape velocity and gravity are relative to the earth and not the asteroid. Wouldn't it be the gravity with respect to the asteroid I need? Pion: When it came to the potential energy...
  8. J

    Asteroid Radius problem

    Homework Statement Asteroids have average densities of about 2,660 kg/m3 and radii from 470 km down to less than a kilometer. Assuming that the asteroid has a spherically symmetric mass distribution, estimate the radius of the largest asteroid from which you could escape simply by jumping off...
  9. J

    Help with Tension problem

    Homework Statement A string is wrapped several times around the rim of a small hoop with radius 0.0800 meters and mass 0.344 kg. If the free end of the string is held in place and the hoop is released from rest calculate the tension in the string while the hoop descends as the string...
  10. J

    What equation do I use?

    Homework Statement Earthquakes produce several types of shock waves. The most well-known are the P-waves and the S-waves. In the earth’s crust, the P-waves travel around 7.0 km/s while the S-waves move at about 3.6 km/s. The time delay between the arrival of these two waves at a seismic...
  11. J

    Trouble finding velocity equation

    Thank you for the help. I believe I was leaving out the constant that is added to the equation when integrating. Thanks again!!
  12. J

    Trouble finding velocity equation

    Homework Statement The problem given has a(t) = C*t where C is a constant and equals 1.2 m/s^3 and t is time. It says velocity after 1.0 second is 5.0 m/s. The question is, what is the velocity after 3.6 seconds. I don't know if I can integrate to get the velocity equation or not. Please...
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