[Tom Crawford (OP)]

In completing a 100 metre sprint, would there be an advantage to be gained if the following were factored into the elapsed time equation, considering that times are measured in 100th of a second?

1) the earth is spinning from east to west - so therefore affects the sprint in that direction (i.e. from east towards the west)

2) the earth travels its fastest in m/s (0.4651 km/s) at its widest point (i.e. along the equator) - therefore sprint east to west at the equator.

[evan_au]

1) the earth is spinning from east to west - so therefore affects the sprint in that direction (i.e. from east towards the west)

The challenge for a sprint is to start off stationary (relative to the starting line) and end 100m away, traveling as fast as possible away from the starting line.

Let's say that the race is held at a latitude where the Earth is rotating at 500km/h towards the East.
The Start Line and the Finish Line are rotating at 500km/h towards the East.
Just before the race, the runners are rotating at 500km/h towards the East.

Regardless of whether the race is run towards the East or West, the athletes must accelerate  their own mass to the fastest possible speed over that 100m, relative to the start line.

So no, the direction would not affect the race (assuming there were no wind).

2) the earth travels its fastest in m/s (0.4651 km/s) at its widest point (i.e. along the equator) - therefore sprint east to west at the equator.

In this case, the Earth is rotating at 1700km/h towards the East.
The Start Line and the Finish Line are rotating at 1700km/h towards the East.
Just before the race, the runners are rotating at 1700km/h towards the East.

The athletes must accelerate  their own mass to the fastest possible speed over that 100m, relative to the start line.
So the latitude will not affect the speed of the race.

One factor that does affect running speed is altitude. Provided the athletes have trained for altitude, the reduced air pressure means less wind resistance, and faster times in a sprint. The 1968 Mexico City olympics broke a large number of records.

[chris]

Winds will make a difference though, won't they. So where on Earth are races best run to take advantage of prevailing winds?

[evan_au]

Apparently, a record cannot be registered if the wind speed is above 2 m/s.
- I guess this is one reason that the Olympics are held in a high stadium - so the winds at ground level are controlled.
- ...and I suppose they want a large audience, too!

So I guess the best place to run a race is where there is a steady wind of 1.9m/s, and you run downwind
- I don't think it would help me beat Usain Bolt
- But it might let Usain Bolt beat Usain Bolt!

See: https://en.wikipedia.org/wiki/Wind_assistance