The discussion revolves around the role of torque in rotational motion, particularly in the context of a test tube in a centrifuge. Participants explore the relationship between angular speed, torque, and the forces acting on the system.
The discussion is active, with participants providing insights into the nature of torque and its relationship to angular speed and acceleration. Some guidance has been offered regarding the interpretation of the free body diagram (FBD) and the role of forces in determining torque.
There are references to specific values of angular speed and the need for clarity on the forces acting on the test tube. Participants express uncertainty about the physical application of forces and their representation in the FBD.
It does create a torque on the wall+floor system. When allowed to touch the ground, it will cause a horizontal frictional force on the ground, towards the wall, and an equal and opposite horizontal force on the hinge at the wall. It cannot create a torque on itself.eterna said:wouldn't the initial angular speed of 50rad/s cause some rotation about the axis at B (so shouldn't the FBD include a torque about B?)
As paisiello2 says, it's the torque required to achieve the angular acceleration the tube undergoes. You need to compute that acceleration.http://postimg.org/image/nad9b9rqn/
And in this question, I don't know what Mz is. Is it due to the angular speed of 60000rpm?
I don't understand that comment. The question asks for net force and torque. It doesn't care how that is applied physically.paisiello2 said:What's missing is the reactions of the clamp that holds the test tube in place in the centrifuge.
No, it's the net torque required to make the test tube's angular velocity increase at a certain rate. It is independent of where the forces are applied. They might be large forces along lines that are close together, or smaller forces on lines that are further apart.paisiello2 said:I was referring to the FBD. The value of Mz will depend on where the forces are applied.