Yes absolutely, Roller Coasters ( depending on the type ) are very able to descend down a vertical angle. Vertical Drop , Dive , Eurofighters roller coaster and more can drop down a vertical drop, some roller coasters can even descend down steeper than vertical drops!!
A website I always go to for my info on roller coasters is ultimaterollercoaster.com
There is no unlock code for Roller Coasters in Tycoon 3. To unlock the roller coasters you must go into career mode and complete the scenarios.
Gravity
if you go to aceonline.org and go to the census section then you will be able to find out. There are 2,695 total roller coasters in the world.
yes yes yes
A chain.
roller coasters!
If the roller coasters are not too strenuos and you don't feel too much pain when riding, go for it!
The voyage roller coasters top speed is 67.4mph
No, only one of them (Dueling Dragons) goes upside down.
Roller coasters are much safer than skydiving. Roller coasters breakdown very rarely and deaths hardly ever happens. When you go skydiving so much can go wrong. You may hit a tree, not deploy your parachute fast enough, or have a crash landing.
They wanted to make new kinds of roller coasters just like they wanted to make them higher.