B Calculating the torque needed to rotate a drum

[jonas_biermann]

Imagine this: You have a drum with a radius of 12cm, around that drum is a toothed belt which is connected to a motor. The drum weighs 10kg
The motor should be placed under the drum

How would I calculate the amount of torque needed to rotate the drum

I don't have any idea how to calculate this but it would be nice if somebody could answer :)

 

[Arjan82]

This question is unanswerable with the information you've provided. It really matters a lot if the rotation is accelerating, and if so what the mass moment of inertia around the axis is, if the drum is doing any work (like if there is maybe stones inside it to be fractured or whatever), if there is friction, etc. etc.

 

[jonas_biermann]

This question is unanswerable with the information you've provided. It really matters a lot if the rotation is accelerating, and if so what the mass moment of inertia around the axis is, if the drum is doing any work (like if there is maybe stones inside it to be fractured or whatever), if there is friction, etc. etc.

The accelaration is static. There are plants in the drum but the center of mass is in the middle of the drum. For my example friction can be neglected.

 

[Arjan82]

If there is no friction and no acceleration, and the drum does no other type of work, then the torque is zero

 

[berkeman]

around that drum is a toothed belt which is connected to a motor. The drum weighs 10kg
The motor should be placed under the drum

How can the motor be under the drum if there is a horizontal belt connecting them? Or are they both horizontal and the belt is vertical, and you are tumbling something inside the drum?

For my example friction can be neglected.

What about the motor bearing friction, and the losses in the belt drive?