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Topic: Four-Man Bobsled

external image bobsled-7.gif
Questions:
*1. How do all four men fit in the bobsled and what are there jobs?
*2. How does the bobsled pick up speed during the race?
*3. What are the different parts of a bobsled?
*4. How does friction affect the speed of the bobsled?
*5. How does the pilot/driver of the bobsled steer the bobsled?
*6. What do the crewmen and the brakeman do during the bobsled race?
*7. Does the way the pilot steers the bobsled affect the speed of it?
*8. What are the other factors, besides friction, that affect the speed of the bobsled?
*9. What is the "push off" at the beginning of the race?

*Answered Questions

Notes For Us: http://adventure.howstuffworks.com/outdoor-activities/snow-sports/bobsled2.htm

1. All four men in the bobsled fit very closely in the bobsled. The driver (pilot) is in the first man in the bobsled and is in charge of steering it. After the driver, there are two crewmen who are in charge of giving the bobsled speed at the beginning of the race by running and then leaning forward to give the bobsled more speed. Behind the crewmen is the brakeman who also helps increase the bobsled's speed, but most importantly pulls the brake at the end of the race after the bobsled has crossed the finish line.
2. The bobsled doesn't pick up speed during the race. The way it gains speed is during the "push off" at the beginning of the race.
3. A bobsled is made up of many parts that make it glide smoothly along the ice while it racing. Probably the most important part of the bobsled are the runners. The runners are like skiis underneath the bobsled that allow the bobsled the go smoothly on the ice. The runners themselves are blunt and it is against the rules to apply lubricant to them to make them go faster on the ice. Another important part of the bobsled is the fiberglass skull that the driver, crewman, and brakeman sit in. Also part of a bobsled are handles on the inside for the crewmen and brakeman to hold onto during the race. The brakeman and the crewmen have bars to push at the beginning of the race to make the bobsled go faster. The brakeman's push bars are fixed into place, but the crewmens' push bars are retractable.
4. There is little friction between the bobsled's runners and the ice. Since there is little friction, the bobsled can travel easily and fastly down the track.
5. The way the pilot steers the bobsled has changed since the 1960's. Before the 1960's, the pilot would steer the bobsled with a steering wheel. Now, the steering system is a system of pulley that have rings attached to the end of them. If the pilot wants to steer the sled left, he pulls on the left ring and pushes the right ring toward the front of the sled. If he wants to go right, he pulls on the right ring and pushes the left ring toward the front of the sled. If the pilot want to go straight, he doesn't pull the rings one way or another, he simply just keeps them straight.
6. A crewman's job is to get the bob moving as fast as possible at the start of the race. The heavier the crewmen are, the faster they will go down the track. During the race, the crewmen and the brakeman have to bend over so that they reduce wind resistance.
7. The way the pilot steers the bobsled does not affect the speed of it since all steering systems are alike. The steering system is made up of a rope and pulley system. To steer the bobsled left, the pilot simply pulls the left steering ring. To steer the bobsled right, the pilot simply pulls the right steering ring.
8. Some other factors of force that affect the speed of the bobsled are wind pressure, centrifugal force, gravity, and drag. Wind pressure, also called wind resistance, is the force of wind pussing against the sled. The bobsledders can eliminate wind resistance and drag by crouching in an aerodynamic position while in the bobsled. Centrifugal force is the force is the force which describes the pressure that is exhibited around a central point. Gravity is the force that is pushing down on us. This affects the bobsled because it is pulling it to the bottom section of the track when you need to be in the center of the track. Drag is air passing around the bobsled. Drag slows the bobsled down.
9.
The push off is when the bobsledders push the sled to give it speed before the race. It usually takes about 6 seconds and a good push off is crucial to the race. After pushing off, the bobsledders jump into the bobsled and crouch down in an aerodymaic postion to reduce drag which will help the bobsledd go faster. Usually the driver gets in first and the brakeman last. Then they fold the retracable push bars into the bobsled.






Things We Need To Do:external image bobsled-10.gif
1. Answer questions above.
2. Create more questions.
3. Plan our project.


Things We Have Done:

1. Created questions we need to answer.
2. Chose what format our project will be.

Sources:

http://adventure.howstuffworks.com/outdoor-activities/snow-sports/bobsled4.htm

http://www.cbc.ca/olympics/history/story/2009/11/25/spo-essentials-bobsleigh.html