To experience a sensation of zero gravity, an average human would need to travel at a speed that counteracts the force of gravity. In Earth's gravitational field, which has an acceleration due to gravity of approximately 9.8 m/s², this would require achieving orbital velocity.
Orbital velocity is the speed at which an object must travel horizontally to maintain a stable orbit around the Earth. It is influenced by the radius of the orbit. For a low Earth orbit (LEO), which is relatively close to the Earth's surface, the average orbital velocity is around 28,000 kilometers per hour (km/h) or about 17,500 miles per hour (mph).
At this speed, a human in a spacecraft would experience apparent weightlessness or zero gravity due to the continuous free-fall state around the Earth. However, it's important to note that achieving and maintaining such velocities and orbits requires specialized equipment, such as rockets and spacecraft, as well as careful engineering and planning. Traveling at this speed on the ground is not feasible with current technology.