I'm not a pilot so could someone tell me what happens when you're going down the runway and just as your reach this point, something happens to the aircraft. A talking head on TV said you'd take off, go round and land again.
Before takeoff you compute a number of speeds including V1, VR and V2 among them
V1 is the Velocity at which you can stop in the remaining runway or lose an engine and takeoff in the remaining runway. V1 is computed a number of different ways so Airline A may not have the same V1 for the same airplane with same conditions.
We generally break the takeoff into calls with a call coming around 80kts. This affords the crew the chance to compare information and to see that all systems are operating correctly. If there is a problem, the crew can reject. The 80kt call also is the point between a low speed and a high speed reject. Below 80, a problem is cause for reject. Above 80kts, you reject only for engine fire or engine failure.
At V1, you go. A 2 engine airplane will get airborne (according to data) and will fly on one engine. Crews are trained to go after V1, solve the problem and then land.
The likelihood that you will be able to stop the airplane on the runway after V1 becomes increasindly small. If I remember the numbers correctly, near V1, the airplane is accelerating at around 10kts/sec so any delay means less runway to stop on and more mass to arrest.
The Vr speed is the velocity at which you begin pulling the nose up (rotate) and V2 is the minimum safety speed once you get in the air.