Physical Science 8th grade (1).pdf

The two offer quite different riding experiences a

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The two offer quite different riding experiences. A wooden coaster is often a rougher and “wilder” ride. This is because wood tends to be less rigid than steel. A wooden coaster’s tracks usually move anywhere from a few inches to a few feet in response to the force of the cars rolling on the rails. The track is designed to do this; its swaying makes for a frightening ride, which is what riders want, don’t they? Chapter 12 Connection
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259 U NIT 5 M OTION AND F ORCE If you are a coaster enthusiast, you know that some wooden frames include inversions. An inversion is when the roller coaster’s cars are upside down. And some cars fly through steeply banked (though not inverted) curves called “overbanked” turns. Most wooden tracks cannot support inversions, and overbanked turns don’t work as well in wood. On wooden coasters, the motion is mainly up and down. That is more than enough for designers to still create thrilling wood roller coasters for big amusement parks. How a roller coaster makes its thrills While they have are clearly different, wooden and steel roller coasters have even more in common. They both rely on rapid changes in velocity to provide excitement. When your velocity changes rapidly your body can feel weightless, like you are falling. You can feel sudden sideways forces, like trying to turn a corner too fast in a car. You can even feel pressed into your seat with twice your normal weight. The challenge to a roller coaster designer is to create rapid changes in velocity that also keep the rider safe! Gravity applies a constant downward force on a roller coaster car. The anticipation builds on the first big hill as the motor drags the car slowly up to the top. Upon reaching the top, the car picks up speed as it seems to fall down the first big hill. The first hill is usually straight so the car gains velocity by increasing its speed. This is where you feel weightless, like you are falling because, you are falling ! The next change in velocity comes in the first turn. The coaster’s tracks constrain the car so it can only move along the track. A rapid change in the car’s velocity vector is created by forcing the car to make a sharp turn at high speed. This is where you feel thrown to one side of the car or get squashed against your fellow thrill-seekers. The speed of the roller coaster car stays about the same through the turn. The change in velocity is in direction, not in speed. Some roller coasters feature corkscrew-like tracks that whip the car through a combination of vertical and turning motion that puts everyone upside down. Here is where you feel pressed into your seat with more than your usual weight. This feeling is created by changing the direction of the velocity vector in the vertical direction, when the car curves over as it speeds through the corkscrew. Because of the tight turns and high speeds, corkscrew tracks must be extremely strong. Wooden roller coasters could not have supported a corkscrew at the speeds of modern steel coasters.
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