Question

Design a roller coaster.

Answer 1

1. Because the cart on the coaster must get all of its power from this first hill. 
2. It must be smaller because if it was bigger the cart would roll backwards without enough power.
3. an upward climb that is too steep.

I answered the first 3 but try to do the last two by yourself. They are very easy once you figure it out. Try searching the definition of the main points. :)