Which of the following statements is true about escape velocity?

Which of the following statements is true about escape velocity?

• A. It's constant regardless of the object's weight.
• B. It decreases with altitude.
• C. It is equal to the speed of sound.
• D. It is the same on all planets.

Answer: (A)

Escape velocity is defined as the minimum speed required for an object to break free from the gravitational attraction of a celestial body without any additional propulsion. The correct statement is that escape velocity is constant regardless of the object's weight. This principle arises from the fact that escape velocity depends solely on the mass and radius of the celestial body from which an object is escaping, rather than on the mass of the object itself. In other words, it takes the same energy to launch any object, regardless of its mass, up to the escape velocity, because gravitational potential energy is a function of the mass of the planet and the distance from its center.

To provide context for why the other options do not accurately describe escape velocity:

• Escape velocity does not decrease with altitude; instead, it slightly increases as you move further away from a planet’s surface, since it depends on the distance from the center of the planet.

• Escape velocity is not equal to the speed of sound, as speed of sound is dependent on the medium through which it travels (like air or water), whereas escape velocity relates to overcoming gravitational forces.

• Escape velocity varies from one celestial body to another, based on their mass and radius, meaning it is not the same across all planets.