Question

What do you mean by bending moment at hinge between two supports?

Answer 1

To answer as simple  as possible, bending moment will develop when the slope due to bending of beam is obstructed.In simple support and roller supports, formation of slope is not restricted. so support  moment is zero. At the same time bending moment at midspan is maximum (consider UDL is applied throughout span) because the slope at mid span is            zero. Where is in fixed support  and continuous support, support moment is not zero sonce the slope of beam is zero at those supports