A roller coaster is a machine that depends on potential and kinetic energy. The cars of the train are pulled up the first steep hill, which builds potential energy for the rest of the ride. This first hill is called a lift hill, which is usually the tallest, and is essential to the remaining trip for the cars on the track. Once the train cars crest the lift hill, gravitypulls the front of the train down the tracks. The higher the hill is, the greater the distance that the train can run. At the top of the hill, the potential energy becomes kinetic energy.

Question

Gravity is channeled through the train tracks. As the car leaves the lift hill, the train begins to fall down the track. This force causes the cars to accelerate, increasing the speed. Once down the lift hill, the next hill causes gravity to place a downward force on the back of the train, causing deceleration. The train will continue a forward velocity, however, if the hills are of appropriate height. This movement reflects Newton’s first law of motion. Once the train is in motion, it tends to stay in motion. At the top of the next smaller hill, the energy of the train changes from kinetic energy back to potential energy, and the ride continues. Most roller coaster hills become smaller as the ride progresses. This design allows the train to change its energy between potential and kinetic energy until frictioneventually causes the energy reservoir built by the lift hill to be entirely spent.

Fluctuations in Acceleration

Most roller coaster enthusiasts love not only the height and the speed of the attraction, but also the thrilling sensation. As the train moves down the track and picks up speed, the rider experiences acceleration. The force of gravity during this “fall” pushes the rider’s body into the seat. This sensation can also cause “butterflies” in the stomach as the body senses the increased speed. As the train climbs another hill and experiences deceleration, the body no longer feels the push of gravity, but the next ride down a hill brings back the sensation. For some riders, this fluctuation brings the excitement associated with riding a roller coaster; for others, the sensation can cause nausea and fear. It is the force of gravity and acceleration that makes roller coasters the attractions that they are.

The Differences in Coaster Materials

Traditional roller coaster tracks were made of wood and relied on steep drops and sharp curves to thrill the rider. The next set of designs for coasters included a track made of steel, which frequently included vertical loops. Recent designs have blended these two types of coasters and use technology to create the safest designs that offer the most thrills for the rider. Today’s designs and materials allow builders to create rides that can reach a traveling speed of over 100 miles per hour, with even taller coasters being planned for the future. Those who love to ride a roller coaster can look forward to even greater thrills with increased speed, height, and gravitational forces.

Multiple Choice Question
What is the purpose of the first sentence of the beginning paragraph of the article?

A.
to draw the reader into the article

B.
to offer an explanation of the sensations experienced by riders

C.
to introduce the topic and the scientific vocabulary of the paragraph

D.
to provide key details about and explanations of the mechanics of a roller coaster

Answer 1

The purpose of the first sentence of the beginning paragraph of the article is:

C. to introduce the topic and the scientific vocabulary of the paragraph