Answer:
3. Newton's first law, or the law of inertia.
4. The balloon is filled with air, and is pushed by the air releasing from the balloon.
5. Newton's first law says any object at rest stays at rest and any object in motion stays in motion, unless affected by an outside force, the outside force is air resistance.
6. The weight is forcing the balloon down and there is some friction. Also, the air resistance acting upon the balloon is slowing it down. The balloon will also lose all of the air in the balloon.
