From the time you start moving to the time you stop...
Velocity is constant when the middle of the roller coaster is parallel with the ground (when the tangent of the curve the roller coaster is on has a slope of 0 at the center of mass of the roller coaster).
Vertical Velocity - roller coaster - was created in 2001.
the roller coaster would crack and break apart because of the velocity. It is to much for a roller coaster to handle.
The roller coaster increases kinetic energy when its velocity is increasing.
Roller Coaster Rumbler happened in 1989.
Going up and down
You're not giving quite enough information. At the moment you are interested in, is the roller coaster moving freely on the track, or is it under the control of a cog or other system? Is the roller coaster on its way down an incline, or on its way up?
it exploded
head cuncusion
I think you will have to start from the beginning of your location in Roller coaster Tycoon 2.
it can maybe break
The translation of the English word, 'Roller Coaster' is..Roller Coaster