Do not use an improvised lever through the sink opening. A wooden handle does not make a powered or obstructed mechanism safe, and it can break, slip or damage parts.
What the observation tells you
A stationary disposer may be jammed, electrically disconnected or stopped by protection; its appearance does not distinguish these situations. Applying force from above can also move the appliance's mounting or leave another object in the chamber. Never substitute your hand for a tool.
A useful next step
Safely isolate the appliance and consult the precise owner instructions. Use only a clearing procedure they explicitly permit; otherwise arrange assessment with a description of the material involved.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.