The speed of sound, also known as Mach 1, varies depending on the medium through which it travels. In dry air at sea level and at a temperature of around 20 degrees Celsius (68 degrees Fahrenheit), the speed of sound is approximately 343 meters per second (1,125 feet per second), which is roughly 1235 kilometers per hour (767 miles per hour).
In terms of reaching or exceeding the speed of sound with various vehicles:
Cars: While some land speed record vehicles have reached extremely high speeds, they have not surpassed the speed of sound. The fastest land speed record achieved by a car is around 1,227.9 kilometers per hour (763.035 miles per hour), set by the Thrust SSC in 1997. Reaching the speed of sound with a conventional car is currently not feasible due to the immense aerodynamic and engineering challenges.
Planes: Certain military aircraft, such as fighter jets, are designed to fly at supersonic speeds, exceeding the speed of sound. These aircraft are known as supersonic aircraft and can travel at speeds faster than Mach 1. However, commercial airliners typically operate below the speed of sound, known as subsonic speeds, for efficiency and comfort reasons. Breaking the sound barrier with commercial planes would present safety and practical challenges.
Spacecraft: In the Earth's atmosphere, spacecraft must typically launch at subsonic speeds and then gradually accelerate to reach orbital velocities, which are much higher than the speed of sound. Once in space, spacecraft can travel at incredibly high speeds, but they do not break the sound barrier again since there is no air in space for sound to travel through.
Space Shuttles and Reentry: Space shuttles and spacecraft returning to Earth from space experience reentry forces that can push them into supersonic speeds. During reentry, the friction with the atmosphere generates intense heat, and the vehicles can create shockwaves as they exceed the speed of sound.
In conclusion, while certain aircraft and spacecraft can reach or exceed the speed of sound, typical land vehicles like cars do not have the capability to achieve such high velocities due to engineering limitations and safety concerns. Breaking the sound barrier remains a significant engineering challenge and is mainly limited to specialized military aircraft and spacecraft designed for such purposes.