What does groundspeed equal on takeoff?

Groundspeed on takeoff is defined as the actual speed of an aircraft relative to the ground. To calculate groundspeed, we can use the relationship between true airspeed (TAS) and the effects of wind.

When an aircraft experiences a tailwind during takeoff, the wind is pushing the aircraft forward in the same direction that it is traveling. This means that the groundspeed will be increased by the speed of the tailwind. Therefore, when calculating groundspeed in the presence of a tailwind, the correct approach is to add the tailwind's speed to the true airspeed.

In contrast, when considering headwinds, which oppose the direction of travel, the true airspeed would be diminished by the headwind's speed. Thus, the correct relationship to determine groundspeed when a tailwind is present is to add it to the true airspeed.