This is where you can design your own roller-coaster.
Roller-coasters are trains that run along rising and falling tracks. The trains are pulled up to the highest point and then allowed to run down the track, powered by nothing other than gravity.
In an upward turn the roller-coaster is forced to change direction. The force on the train makes the passengers feel much heavier than normal.
Similarly, in a downward turn the roller-coaster is pulled downwards by the track.
The size of the forces felt in the turns is what makes the roller-coaster exciting to the passengers. Quick turns in either direction will make the passengers feel heavy and cause a rush of excitement.
Too much force may make the passenger sick, or even pass out, as it restricts the flow of blood inside the body.
When designing your roller-coaster, bear in mind the force at each point. The tighter the curve, the higher the acceleration. But don't go too far - a force of more than 5 times your own weight in the turn is considered harmful.
Remember, the train will slow down slightly due to friction as it runs along the track. The height of the hills it can climb will therefore get smaller - it can never go higher than the starting point!