Design a roller coaster.

i need with the questions on this page.

and also questions:
1. why does the first hill have to be the highest?
2. why can't the next hill of the roller coaster be as high as the first?
3. what forces slows it down?
4. the kinetic energy is change to what kind of energy by this force?
5. what is the approximate percentage of gpe/ke at different points on your roller coaster labeled a, b,c?

Two manned satellites approaching one another at a relative speed of 0.550 m/s intend to dock. the first has a mass of 2.50 ✕ 103 kg, and the second a mass of 7.50 ✕ 103 kg. assume that the positive direction is directed from the second satellite towards the first satellite. (a) calculate the final velocity after docking, in the frame of reference in which the first satellite was originally at rest.(b) what is the loss of kinetic energy in this inelastic collision? (c) repeat both parts, in the frame of reference in which the second satellite was originally at rest. final velocity(d) loss of kinetic energy = ?