HI to all

I need the formula to calculate the required torque to rotate the shaft.

As they say in the standardized tests:

"It is not possible to answer the question with the information given."

Add some information about your problem.

The more torque you apply the faster a sfat will accelerate:

Torque = I times Alpha

where I = moment of inertia of the shaft, and alpha is the desired rotational acceleration.

This assumes there is no friction or other opposing forces.