ELIF: How does drafting work? Is it possible for humans to run behind a large vehicle that’s traveling at speeds faster than they are capable of reaching?
In: Physics
Drafting is a way of taking advantage of another object’s work to make your work take less energy. For example, if person ‘A’ is running, the force they have to exert to move forward is the amount of force to move their body plus the amount of force necessary to push the air ahead of them out of the way. Now the air that gets pushed out of the way swirls around person ‘A’ and fills in a semi-vacuum behind them. If person ‘B’ can run close enough behind person ‘A’, they won’t have to exert as much force to move the air in front of them, and can possibly even get a little push from behind from the air filling in behind person ‘A’ Now ‘A’ and ‘B’ are running at the same speed, but ‘B’ is using a lot less energy than ‘A’ to maintain that speed. When ‘A’ eventually tires and slows down, ‘B’ can now kick in that energy that was conserved by drafting ‘A’ and continue running for a longer period of time.
Team races, like bicycle racing, use this as a strategy. A team of racers will draft in a single line, rotating the lead position among the lower ranked members of the team to preserve the energy/endurance of the star member, who will be unleashed toward the end of the course to sprint into the lead and win that leg of the race.
It’s also why birds fly in a ‘V’ formation. The trailing birds are drafting in the wake of the lead bird and they’ll rotate that role among themselves allowing the group to fly further in a day than any individual bird could alone.
Latest Answers