"The weight of an exercise book in picture A (where the centre of gravity is not on the axis of rotation) rotates so it moves towards the second position in picture B (where the axis of rotation goes through the centre of gravity). Explain why." I don't believe any equations are necessary for this question. I understand the pure concept of this question. The centre of mass/gravity is where all the weight of the object is centred, therefore it makes sense that an object would rotate to make that point central. However, I am struggling with the actual movement and position. For example, the book's centre of gravity is in the centre, so why does it rotate downward and then stop? The actual centre doesn't change position, so why does the book need to rotate? I apologise if I haven't made it clear what I'm enquiring about, please let me know if further details are needed.