1. The Basics- Acceleration, Gs, Transitions

Newton 2 can be downloaded here: No Limits Exchange

Before we can even talk about Newton 2, it is important to have a good understanding of what acceleration, G’s, and velocity are. You may be thinking, “Acceleration is when you speed up, and G’s are the pull you feel when you go around a loop, and velocity is how fast you’re going.” While that is partially correct, there is much more to it.

Velocity is the measure of speed in a certain direction. Acceleration is defined as the rate of change of velocity over time. Gs are a measure of Acceleration. 1 G is equal to the acceleration due to the force of gravity (at sea level and assuming no air resistance or friction): 32.2 feet/second squared...or for the purposes of using Newton 2, 9.81 meters/second squared.

Given these definitions, it is possible to accelerate without gaining or loosing any speed. Ex. You are in a car that is driving a constant 30 mph and you round a 90 right turn in the road. Say it takes 6 seconds for your car to travel from the start of the turn to the end of the turn. Your acceleration during those 6 seconds would be a 15 degree change in direction (and velocity) per second. Consider the steering wheel of the car during such a turn. What do you think the steering wheel would look like?...A smooth turn of the wheel transitioning into and out of the bend in the road, or a sudden jerk of the wheel as the turn starts and ends abruptly? If the steering wheel is turned suddenly to start and turned suddenly to stop the turn, there would be a sudden application and relief of centripetal force (the force which accelerates the car towards the center of the circle). Even if the force was not very high- say only 0.5 Gs- it would still be uncomfortable to the passengers in the car because there is no smooth transition in and out of the turn.

Now consider how much less painful making the turn would be if the person driving gradually moved the steering wheel from a position that changes the car’s direction by 0 degrees per second to a position that changes the car’s direction by 15 degrees per second. Not only would you not hit your head on the window, you would enjoy the car ride a lot more...and be less scared for your life. The gradual application of the force makes all the difference.

In fact, the gradual application of force is just as important in roller coaster building as the magnitude of the forces themselves. It doesn’t matter what direction you are changing into or headed, if a turn starts suddenly, the coaster car “drops out from under you” too quickly, or the radius of a curve in the track changes quickly, you may have a problem with transitioning forces. A commonly used term among No Limits users to describe awkward force transitions is "pumpy." Though pumps are difficult to prevent, it is possible to build a coaster without them. If you are riding along in a coaster car and you are hit with 3 vertical G’s suddenly, it may knock the wind out of you. 3 Gs is a very reasonable and tolerable amount, but when you are hit with a sudden increase all at once, it is unpleasant. You riders would thank you if you avoided it. A better way of designing that section of track would be to transition gradually- say you start at 1 G then transition to 3 Gs, passing 1.25 , 1.5, 1.75, 2, 2.25, 2.5, 2.75, along the way.

I will elaborate on transitions in later editions of the tutorial, but for now I want to make it clear that transitions are very important! Transitions are what Newton 2 is all about. In the next tutorial, I will explain all the parts of the Newton 2 interface. In the tutorial after that, I will explain the different types of transitions and how and when to use them.

Note: The train applies centripetal force (center-seeking) to the riders of a coaster, forcing them to follow a curved path. The reactive centrifugal force is what keeps the riders in their seats. It can be argued that centrifugal force isn't really a force but an observation of inertia acting under certain set of circumstances (I.E. It is the reaction to the action of the centripital force). For this reason, this is the third and last time the words "centrifugal force" will appear in this tutorial series.