Recent content by jj8890

  1. J

    What is the magnitude of the Reaction Force?

    Homework Statement In my homework we are asked to find the magnitude of the reaction force at the pivot at a instant and earlier in the problem we found the magnitude of the angular speed at one instant, the magnitude of the angular acceleration at the same instant, and the magnitude of the...
  2. J

    Angular speed question .

    Homework Statement As a result of friction, the angular speed of a wheel changes with time according to d θ/d t = ω_0 e^(−σ t) , where ω0 and σ are constants. initial angular speed = 5.45 rad/s σ =.23913 Determine the number of revolutions the wheel makes after 2.33 s . Answer in units of...
  3. J

    Quick tangential speed question

    So the ratio would be 1/4 or would you have to square the r term making it 1/16?
  4. J

    Quick tangential speed question

    So, if v=2*pi*R/T and T^2=r^3, wouldn't v/2*pi*r =r^3 and one r would cancel out making it v=2*pi*r^2 so for the ratio, 2*pi *(4)r^2 =2*pi * r^2 and everything would cancel out except the 4 making the answer 4 like I originally thought?
  5. J

    Quick tangential speed question

    T^2=r^3 so since t=w/2*pi^-1: r^3=(w/2*pi^-1)^2 I'm sorry but i feel so confused I appreciate you being patient with me but where would I go from here. The thing is that we haven't used angular velocity in my class yet and i didn;t know that the period equaled w/2*pi^-1 until i looked about 3...
  6. J

    Quick tangential speed question

    The angular velocity specifies the angular speed at which an object is rotating along with the direction in which it is rotating so it is a portion so...when i looked it up the period equals (w/2*pi)^-1 where w is the angular velocity...where would I go from there?
  7. J

    Quick tangential speed question

    I'm sorr, i don't see wher eyou are coming from. Kepler's Laws are: 1. The path of the planets about the sun are elliptical in shape, with the center of the sun being located at one focus. (The Law of Ellipses) 2. An imaginary line drawn from the center of the sun to the center of the planet...
  8. J

    Quick tangential speed question

    Homework Statement Two satellites A and B of the same mass are going around the Earth in concentric orbits. The distance of satellite B from the earth’s center is four times that of satellite A. What is the ratio of the tangential speed of satellite B to that of satellite A? Homework...
  9. J

    Circular orbit question please check answers

    I also got 1016.21 N when recalculated...thanks
  10. J

    Circular orbit question please check answers

    The 86400 = 24 hrs in seconds, the period. I also thought that the force was high...I'll recalculate.
  11. J

    Circular orbit question please check answers

    [SOLVED] Circular orbit question...please check answers Homework Statement Given: G = 6.67259 × 10^-11 N m^2/kg^2 . A 956 kg geosynchronous satellite orbits a planet similar to Earth at a radius 201000 km from the planet’s center. Its angular speed at this radius is the same as the...
  12. J

    Does gravity work in the opposite direction when moving down on a ferris wheel?

    [SOLVED] basic question about gravity This is just a simple concept question. A person is moving on a ferris wheel around in a circle and the magnitude of the work done on them moving from top to bottom is W=2*g*m*r where m=mass and r-radius of ferris wheel. When plugging in the numbers into...
  13. J

    Work on an object moving in a circle.

    The above was right..thanks
  14. J

    Work on an object moving in a circle.

    Well, if the radius was R and the mass of the person was m_B, would the work done on B by the ferris wheel be 2m_B*g*R because person B moves 2 times the radius...or would I have to include the mass of person A in there somewhere?
  15. J

    Work on an object moving in a circle.

    Well, obviously deltaK=-deltaU so W=-DeltaU or -U_2 +U_1 but where would i go from there? Or am I totally on the wrong path?
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