Applying the dynamics of motion

What features of the athlete’s technique help decrease the time on the run?

Athletes lie down and keep their heads down and toes pointed in order to be as  aerodynamics as possible. They wear helmets and suits that are specially designed as well. By doing that, they can maximumly reduce the amount of air friction. When the friction force decreases to the minimum, the net force on the athlete and the luge increases to the maximum. Then, the acceleration increases to the maximum ( according to the formula Fnet = ma), and that caused the speed increasing to the maximum. Eventually, the time on the run decreases to the minimum.

What features of the luge help decrease the time of the run?

Firstly, the luge is lightweight. Secondly, the bottom of the luge is smooth. Both ways can minimize the friction force between track and luge ( according to the formula Ffriction= μFN，the friction force could decrease to the minimum if normal force or the coefficient of friction decreases to the minimum). Eventually, the time on the run decreases to the minimum( see the answer of question #1 for detailed reasoning).

How can the athlete discover the ideal body position to minimize drag?

Athletes generally spend a lot of time in wind tunnels designed to help them find the ideal body position. Getting experience from actual matches also could help.

How does the terrain (luge course) affect the speed?

Terrain determines the coefficient of friction between the track and the luge.The coefficient of friction determines how big the friction force is. The speed increases if friction force decreases ( see the answer of question #2 for detailed reasoning).

Why is it important for luge track workers to keep the surface as smooth as possible?

The most important reason, besides reducing friction force, is to secure athletes’ safety. Controlling luges in high speed is very hard and dangerous. Even a little piece of tough or sharp matter could cause an unexpected crushing, which is a considerable threat to athletes’ safety. Therefore, it is very important for luge track workers to keep the surface as smooth as possible.

How do luge athletes “brake” their sleds?

Athletes brake by their feet.

Why are large athletes’ shoes covered with thick tire-like treads?

The first reason is that thick tire-like treads could increase the coefficient of friction between track and brake ( athletes’ feet ), thus make braking more effective. The second reason is that the friction force caused by braking is tremendous, so treads are used to protect athletes.

What are the most dangerous parts of a luge course?

The most dangerous parts of a luge course are the turns and turn combinations since athletes are at a very high speed, and the friction force between luge and track is quite small.

What motions/ forces are buffeting the athlete? 

The first one is high velocity. It is very hard for athletes to control the luges with high velocities. The second one is circular motions ( when athletes turn).

How do luge athletes try to maintain (or even increase) their speed?

Athletes have to perfectly balance the opposing forces by finding just the right spot on the luge.

How do luge athletes steer their sleds?

When the luge moves in a straight line, the athlete lies down and keep his or her heads down and toes pointed in order to reduce air resistance maximumly, thus reach high speed. When the athlete has to turn, he or she turns his or her body a little bit. When the athlete has to stop, he or she brakes by his or her feet.

What force pulls the luge down the track?

Gravity pulls the luge down the track.

What 2 forces that work against gravity that pulls the luge down the track?

Those two forces are both friction forces. One is the friction force between air and luge, another is the friction force between track and luge.