1. The problem statement, all variables and given/known data The Hubble Space Telescope is stabilized to within an angle of about 2 millionths of a degree by means of a series of gyroscopes that spin at 1.92×104 . Although the structure of these gyroscopes is actually quite complex, we can model each of the gyroscopes as a thin-walled cylinder of mass 2.00 and diameter 5.00 , spinning about its central axis. How large a torque would it take to cause these gyroscopes to precess through an angle of 1.30×10−6 degree during a 5.00 hour exposure of a galaxy? 2. Relevant equations L=I*ω torque = Ω*L I=mr^2 Ω=Δθ/Δt 3. The attempt at a solution ω=1.92*10^4rpm =2010.62rad/s I=mr^2 =2(0.005)^2 =0.005 Δθ=1.3*10^6deg =7.4484*10^-5rad Δt=5 hours =18000s torque = Ω*I*ω =(7.4484*10^-5/18000)*0.005*2010.62 =4.1*10^-8 Nm This is the wrong answer and I feel as if the torque shold be rather larger by intuition. Any help would be appreciated. Edit: 3.17*10^-12 Nm turned out to be the correct answer, but i'd still like to know how to do this question.