What term describes the speed needed to escape Earth's gravity?

What term describes the speed needed to escape Earth's gravity?

• A. Orbital speed
• B. Escape velocity
• C. Acceleration due to gravity
• D. Terminal velocity

Answer: (B)

The term that describes the speed needed to escape Earth's gravity is "escape velocity." This is the minimum speed an object must reach in order to break free from the gravitational pull of a celestial body without further propulsion. For Earth, this speed is approximately 11.2 kilometers per second (about 25,000 miles per hour). It is important to note that escape velocity is independent of the mass or shape of the object escaping; it only depends on the mass and radius of the planet.

Other terms, like orbital speed, refer to the speed necessary to maintain a stable orbit around a body rather than to break free from its gravitational influence. Acceleration due to gravity describes how fast an object accelerates towards the Earth when in free fall, and terminal velocity is the constant speed an object reaches when the force of gravity is balanced by air resistance, which is unrelated to escaping from gravity entirely. Understanding these terms clarifies the distinction between velocity for orbiting, falling, and escaping gravitational influence.