The do all start on a straight line if the track does not go round a bend.
However when the track is circular and runners are running in lanes, the outside lane is longer than the inside lane. The lane starting position is therefore staggered so that each runner in each lane actually ends up running the same distance.
A staggered start.
Virtually all athletics tracks are 400 metres long. This is why they have a staggered start in 400m races. An 800 metres race is therefore 2 laps of a 400m track.
It starts at 10:10 AM with a staggered start to avoid congestion. In other words the race is run against a computer clock instead of 'gun' time with the elite women jumping off to begin the race and three staggered groups following their lead. Each runner wears a computer chip in their shoe to track them through the course.
No. The staggered start is used to allow a large field (some with in excess of 100 teams) to "spread out" at the line and avoid a "bunching up" of contestants in a race.
In athletics it's called a staggered start, when athletes do not all start from the same start line. They must run a certain part of the race in their own lane before they are allowed to gravitate towards the innermost lane.
A hundred-meter race
The track length is longer for the outer lanes. The starting blocks are staggered so that each runner has an equal distance to the finish line. They have to remain in their respective lanes because of the position where they started, to make it fair to all runners.
You don't.
The 100 meter race started in the 1896 Olympics.
You normally start a 400m race (outdoor track) at the same place as 800, 1600 and possibly 300; which isn't a common event in outdoor track and field anyway
The Distance they run is the same by the end of the race.
The stagger in the 400 meter dash are the different starting points around the first curve that each runner lines up on. Because the track is oval, having everyone start at the same line would be unfair to those running in the lanes outside of lane 1. Basically, the further out you would start, the further you would have to run. for example, By having the starting point for each lane start futher up ,or staggered, around the first turn ensures that all the runners are running the same distance.