How to choose the right motor?

Hi builders,
I'm building an interactive art piece that will rotate a 3.5" HDD hung on the wall. Do you know which kind of low power motor can withstand the weight (500g) while providing good rotation speed?

thank you

You need to understand torque in order to select the right motor, torque is dependent
on how far a force is off-axis, not just how big a force.

If the object to be rotated is in perfect balance minimal torque is needed to turn it,
but there is friction to overcome and (angular) acceleration also requires torque.

If an object is not balanced torque = force x distance (the distance of the centre of
mass from the axis). Force = mg (mass x acceleration due to gravity)

If the object is heavy the motor bearings have to be able to cope with the weight
whether or not it is balanced.

Motors typically state amps per N-m (or other measure of torque), or max torque.
Allow a healthy margin...