Consider a pencil. Now break it in 2. Do it again and it s obvious it gets harder to do it. Why is that? I thought of modeling the problems as a hinged beam with moments applied at both ends having opposite directions and same torque. So basically the length of the beam doesn't affect the moment diagram which constant and equal to the moments. As the beam length change we will still have the same moment distribution so why does it get harder? And what's the reason it breaks near the middle? Thank you.