Roller Coaster Questions

In general, fhe force (F) is constant and the vertical component of Force is the weight of the roller coaster cars and contents (in force units-pounds force, slugs, dynes, or newtons--take your pick). Assumming a frictionless roller coaster, the vertical force component (Fv) is the product of the total force and the slope of the hill.

Its the work (W) that your interested in and work is the product of the vertical component of force and the change in elevation of the first roller coaster hill (W=FvxH). Some of the more common units for work is foot-pounds, newton-meters (Joules), and dyne-centimeters (Ergs).

For further clarification look at Work and Energy

Rap

Change in Potential Energy
You could also look at this as a change in potential energy problem. If you assume the rollercoaster is at rest at the bottom of the hill and will be at rest at the top, then the change in potential energy is:

Work = Mass x Gravitation Constant x Change in Height.

Of course, you also translated the coaster along the ground and there is friction in the track to be overcome, but these should be small compared to the potential energy change.