Name the force which always opposes motion.

A small device pulls iron nails from a distance. Which type of force is involved in this process?

Which force can be used to gather iron pins scattered on the floor?

Which force makes a rolling ball stop on its own?

An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?