Recent content by jenavira

  1. J

    Gravitation acceleration question

    A uniform solid sphere with radius R produces a gravitational acceleration a(g) on its surface. At what two distances from the center of the sphere is the gravitational acceleration a(g)/3? I know that gravitational acceleration = GM/r^2, and that on the surface of the sphere, a(g) = (4 pi G...
  2. J

    Calculating Linear Acceleration on a Rotating Record

    *facepalm* Figured it was something simple like that. Thanks!
  3. J

    Calculating Linear Acceleration on a Rotating Record

    Q: What is the linear acceleration of a point on the rim of a 30-cm-diameter record rotating at a constant angular speed of 33.5 rev/min? I seem to have all the variables and equations in hand - r = .15m and \omega = 3.49 radians/second; v = \omega r ; (radial component of linear...
  4. J

    Solving Collision Problem: Find Angle Between Initial Velocities

    Collision problem After a completely inelastic collision, two objects of the same mass and same initial speed are found to move away together at half their initial speed. Find the angle between the initial velocities of the objects. I've got the equations (2mv)cos theta1 = 2m.5v cos theta2...
  5. J

    Finding the Height of Remaining Soda at Center of Mass's Lowest Point

    A right cyllindrical can with mass M, height H, and uniform density is initially filled with soda of mass m. We punch small holes in the top and bottom to drain the soda; we then consider the height of the center of mass of the can and any soda within it. If x is the height of the remaining soda...
  6. J

    Can You Prove Conservation of Energy in Vertical Stone Throwing?

    I think I've managed it now. Thanks a lot. :)
  7. J

    Can You Prove Conservation of Energy in Vertical Stone Throwing?

    ...right. I'm going to sound like an idiot, but could you go through that accelleration in a bit more detail? I'm still a bit confused.
  8. J

    Can You Prove Conservation of Energy in Vertical Stone Throwing?

    Well, F = ma so a = F/m...and the force in question would be the initial velocity. But I'm not at all sure how that helps...
  9. J

    Can You Prove Conservation of Energy in Vertical Stone Throwing?

    Huh. I'm getting closer. But I still have no idea how I'm supposed to relate the conservation of energy and kinetic motion equations. (It's probably something really obvious, and I'll feel like an idiot for not realizing it sooner, but I've been staring at these for so long...)
  10. J

    Can You Prove Conservation of Energy in Vertical Stone Throwing?

    This is driving me nuts. A stone with weight w is thrown vertically upward into the air from ground level with initial speed v(i). If a constant force f due to air drag acts on the stone throughout its flight, (a) show that the maximum height reached by the stone is h = v(i)^2 /...
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