That is because the roller coaster is designed to accelerate you with enough force to experience more than 1G acceleration. When upside down you are being pulled down with 1G but up with more than 1G so net force is up, not down. Some rides give you 2-3 G up force.
Yes
The Demon in Great America, California. (that was my beginner roller coaster)
Upside down.
inertia
A part where the riders go upside-down.
A part where the riders go upside-down.
so it can get a little speed
Runaway Mountain does not go upside down.
It is a roller coaster that goes 60mph and it goes upside down, it also has some steep drops.
The Tiger & Turtle is a roller-coaster at Magic Mountain Germany. It has steps and slopes that are climbed with human power - in other words, you walk on it. It is a 69-foot roller coaster, which puts the visitor 148 feet above the surrounding countryside of Duisbu, Germany. There is an upside-down loop on the coaster, but you can't actually walk on that part.
The Incredible Hulk roller coaster goes up-side down 4 times last for up to 7 seconds each time.
No, Expedition Everest (Disney) doesn't go upside down but it dose make you get that feeling that you are.