Torque Provided By A Rocket's Thrust

[cjavier]

The Question Is: The 200 g model rocket shown in the figure generates 4.0 N of thrust. It spins in a horizontal circle at the end of a 100 g rigid rod. What is its angular acceleration? Here is the picture:

http://session.masteringphysics.com/problemAsset/1073775/3/knight_Figure_13_24.jpg

However, I am confused that every answer I have seen does not take into account the torque generated by the rod's gravitational pull to produce the Total Torque (Sigma Torque). Why is this?

PLEASE do not just post to me how to get the answer. I have seen this. I also realize that the moment of inertia take's into account the rod. However, I still believe that the gravitational pull of the rod should be accounted for in the total torque. Please, someone with experience explain to me why this is not so.

 

[Doc Al]

You are told that the rocket moves in a horizontal circle, so somehow the torque from the weight of rocket plus rod has already been balanced by the supporting structure.

 

[cjavier]

Question Resolved

HORIZONTAL. I see now. Thank you