The physics behind the Olympic Bobsled; Russia leads, US third after two heats

The United States (team 1) kicked off the two-man bobsled competition in the 2014 Olympics in Sochi, Russia with a time of 56.34 seconds and a max speed of approximately 82.9 mph. Team 1 of the United States placed second in the first heat of the event behind Team 1 of Russia, however, the Americans dropped to third after only the eighth best time in Heat 2.

By Bret Walts

For those unfamiliar with two-man bob-sledding, it is fairly simple, and it can be easily understood for those of you familiar with physics.

THE START:

At the start of the run for the 2-man bobsled, the two participants run behind, or on the side, of the sled to get it off to a quick start. The sled begins in grooves that have been dug in the ice to quickly, and easily, pick up speed before the sled enters the nearly frictionless, icy portion of the track. This is also the part where the participants jump into the sled. In Heat 1, Team 1 USA completed the start in 4.83 seconds and reached a speed of 14.1 m/s by the end of the start. In this quick, but critical segment, team USA covered around 68 meters of distance before they even got into their sled. Finishing this segment quickly can set up a team for a solid run the rest of the race if they can carry the momentum.

Segment 1:

Here’s where the physics of this sport really kick in. The team now enters the nearly frictionless course with high banks and very little room for error. While less friction means a greater amount of speed can be reached, the margin for error is very, very small especially on a narrow track that Sochi presents. Often times, in the most critical, difficult parts of the course, errors will lead to a bump against the wall. The force at which the sled hits the wall will be equally applied to the sled. The greater the force of the hit against the wall, the greater the force applied to the sled and the greater the force applied to the sled from the wall, the larger impact it will have on the sleds speed. This section gives riders time to stabilize the sled and find their balance. In Heat 1, Team 1 USA only had an acceleration of .46 m/s.

Segment 2-3:

bobsledIn this segment, Team 1 USA reached a max speed of 35.4 m/s, up 14.5 m/s from segment 1. This segment had an acceleration of approximately .72 m/s. These segments feature downhill parts of the course and banked curves likely increasing speed and acceleration. Using the formula of distance=speed*time, we notice this segment covers the most distance of the course at approximately 565.3 meters, making this segment the most crucial. This part also features the difficult turn five which has taken many participants out of medal contention in luge and skeleton.

Segment 4-Finish

Much of the last two segments feature banked curves and the sleds can reach speeds over 80 mph! The max speed after two heats was 83.07 mph by Team 1 Russia. So how close was Russia to max speed possible through the curves? In estimating .08 of static friction on the circuit along with assuming the entire distance in this segment is banked, the max POSSIBLE speed to be reached would be around

92 mph. However, we can assume that the entire segment would NOT be banked curves; therefore the max POSSIBLE speed would be less. So what’s that all mean? Russia did pretty good that’s what it means. There is not a lot of improvement Russia could’ve done on that run, and physics proves it.

Russia’s impressive speed bolted them to the top of the charts after two heats and a lead of over three tenths of a second (that’s a lot for bobsled).

Notable Heat 1 Performances

United States 1

Time (s): 56.34

 Max Speed: 82.9mph

Notes: 20 steps before jumping into bobsled

Switzerland 1

Max Speed: 81.96 mph

Time (s): 56.46

Notes: Hit wall

Russia 1

Max Speed: 83.0 mph

Time (s): 56.25

Germany 3

Max Speed: 82.1 mph

Time (s): 56.50

USA 2

Max Speed: 82.5

Time (s): 56.45

USA 3

Max Speed: 82.1

Time (s): 56.73

Jamaica 1

Max Speed: 78.8 mph

Time (s): 8.42

Standings after Heat 2

1.       Russia 1

2.       Switzerland 1

3.       United States 1

4.       Canada 3

5.       Russia 2

6.       Latvia 1

7.       Germany 1

8.       Canada 2

9.       Canada 1

10.   Germany 2

11.   United States 2

12.   Switzerland 2

13.   United States 3

14.   Germany 3

15.   Italy 1

16.   Latvia 2

17.   France 1

18.   Romania 1

19.   Korea 1

20.   Monaco 1

21.   Netherlands 1

22.   Austria 1

23.   Great Britain 1

24.   Czech Republic 1

25.   Korea 2

26.   Australia 1

27.   Poland 1

28.   Japan 1

29.   Serbia 1

30.   Jamaica 1

With only two heats remaining, and a home track advantage, the Russians look to be in good shape for at least a medal. Should Russia perform similarly in the last two heats, Team 1 of Russia could walk away with a gold medal in Sochi.

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