1. Roller coaster Jingting Zhao jxz5212 Tianxin Li tvl5279 Congya Tan cqt5166

2. Topics related in the course Acceleration Potential energy Kinetic energy The conservation law Gravitational force Centripetal force

3. Roller Coaster People love to go to theme parks for fun and I bet the first thing one can think of a theme park is the Roller coaster, or the “screaming machine”. We all enjoy this kind of giant high- speed amusement ride, but we seldom wonder how does it actually works? Now we are going to find out the answer for that.

4. How does the roller coaster work? What you may not realize as you're cruising down the track at 70 miles an hour is that the coaster has no engine. You aren't being propelled around the track by a motor or pulled by a hitch. All the energy needed is to pull the car to the top of the first hill at the beginning of the ride, but after that the car must complete the whole ride on its own. The conversion of potential energy to kinetic energy is what drives the roller coaster, and all of the kinetic energy you need for the ride is present once the coaster descends the first hill..(Amusement Park Physics -- Roller Coaster,n.d.)

6. How does the roller coaster work? As the picture shown, at the top of the hill, the car(roller coaster) possesses a large amount of potential energy. This is given by the gravity pulling it to a great distance. The higher the distance is, the greater the potential energy the car gains. As it reaches to the maximum height, there is no kinetic energy since the velocity is zero but greatest potential energy.

7. How does the roller coaster work? When the car begins to fall, potential energy decreases accordingly due to the loss of the height. On the other hand, kinetic energy begins to increase because the car is speeding up. As a result, the original potential energy is now transformed into kinetic energy. The total energy, however, stays the same according to the conservation law.

8. How does the roller coaster work? When the car is in a falling motion, gravitational force pulls it toward the ground; the car accelerates. When it is in rising motion, the gravitational force applies downward; the car decelerates.

9. You might be curious about how could a roller coaster not falling off from the track at its highest point. How does the roller coaster work?

10. The answer to this question is that at the highest point, the gravitational force will serve as centripetal force (mg=mv^2/r). This force allows the roller coaster to circle around the invisible center of the track, which is part of a circle. Therefore, the roller coaster will not falling off the track and do circular motion instead.

11. New insight After the study of Roller coaster, I suddenly think of my experience of skiing. Skiing is like riding a roller coaster. I don’t necessary need to use the pole and can just simply stand on the ski board then let it slides down from the top of the mountain. At the top of the mountain, I have the largest potential energy and when I start to slide down, the potential energy will transform into kinetic energy due to the law of conservation. Then I realise why people always recommend skiing beginners to ski from a lower hill; because they will have a lower potential energy at the top of hill, so when they slide down the hill the potential energy transfers to a lower kinetic energy, resulted in a lower speed. This is better for a beginner to learn how to control.

12. Bibliography Tom Harris, n.d. How Roller Coasters Work Retrieved from http://science.howstuffworks.com/engineering/structural/roller-coaster.htm http://science.howstuffworks.com/engineering/structural/roller-coaster.htm Amusement Park Physics -- Roller Coaster (n.d.). Retrieved from http://www.learner.org/interactives/parkphysics/coaster.html http://www.learner.org/interactives/parkphysics/coaster.html "Energy Transformation on a Roller Coaster." The Physics Classroom. Www.physicsclassroom.com, n.d. Web. 13 Apr. 2015. Harris, Tom. "Roller Coaster Physics." HowStuffWorks. HowStuffWorks.com, n.d. Web. 13 Apr. 2015.