Hi all. I have a few questions: 1. Is repulsive force present in any certain situation other than magnetic fields? 2. I read that a big enough electromagnet can attract or repel even a human being. Can the same effect attainable from a big enough magnet? 3. What materials are not being affected by this repulsive force? 4. And why a certain material is influenced and others are not influenced by it? Thank you in advance, looking forward for your answers!