1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: PLEASE HELP. Gyroscope question

  1. May 17, 2014 #1
    The problem statement, all variables and given/known data[/b]
    A special purpose fan is mounted as shown in figure Q5 (Ive attached a picture of the diagram). The motor, armature, shaft and blades have a combined mass of 2.2Kg with a radius of gyration of 60mm. The axial position of b of the 0.8kg block A can be slid on the mounting shaft. With the fan turned off, the unit is balanced about the x-axis when b=180mm

    The motor and fan operate at 1725rev/min (180.6 rad/s) in the direction shown. Determine the two values of b that will produce a steady procession of 0.2rad/s about the y-axis.

    I have drawn a free body diagram of unit rotating due to gyroscopic forces (Attached). I worked out the moment of inertia was (60*10^-3)^2*2.2= (7.92*10^-3) kgm^2. I then worked out that the gyroscopic force generated by the fan was (7.92*10^-3)*(0.2)*(180.6)=0.286Nm. I am really confused how to work out the distance that the weight moves either towards or away from the pivot to cause this torque.

    Attached Files:

  2. jcsd
  3. May 17, 2014 #2
    Try summing the moments about R.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted