What is the formula for finding the speed of a roller coaster at point A?

[badtwistoffate]

Roller coaster Vel. Initial=10m/s, Height initial=100m, and the mass of the coaster is 1000kg all at the starting point (*).
Have to find the speed of coaster at point A, point A's height is the same as the starting points, b is 1/2 of a's height, c's height is zero.
Coaster kinda looks like: * is starting point

........../
..._*_..._A_....../
.../----\.../---\..._B_.../
.../------\__/-----\__/----\.../
__/-------------------------\_c_/


I found Vf of the starting point with vf^2=vo^2+2 a deltaH
and used that Vel for Vo when i do it again but for point h.
what should I do?, my Vf of the starting point i got was 45.4m/s

 

[ViewtifulBeau]

vf^2 = vo^2+ 2*a*(xi-xf)

Vo = 10 each time
a = 9.81 each time
xi = 100 each time
xf = height above ground

this should work

 

[kp]

what about conservation of energy?

 

[lightgrav]

I hope ViewtifulBeau realizes that that equation
comes from (as a special case) Energy conservation.

I DO wish you folks would stop treating "g" as an acceleration!