MCQ Detailed View

Escape velocity is the minimum speed required for an object, like a rocket, to break free from the gravitational pull of a planet without further propulsion. On Earth, this velocity is approximately 11.2 km/s. If a rocket reaches or exceeds this speed, it can move into space and overcome Earth's gravity.

Gravity is the force that attracts all objects toward the center of the Earth. A rocket must generate enough kinetic energy to counteract this gravitational pull. The escape velocity ensures that the rocket's motion is sufficient to overcome Earth's gravitational force and reach outer space.

Other options in the question are incorrect:

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  Centripetal force due to Earth’s rotation is unrelated to escape velocity. It affects only the circular motion of objects on Earth.

  
  


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  Pressure of the atmosphere resists motion slightly, but it is negligible compared to gravity and does not determine escape velocity.

  
  


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  Moon’s gravitational pull has very little effect on a rocket leaving Earth; it is Earth's gravity that must be overcome first.

  
  

The concept of escape velocity is derived from Newton’s law of gravitation and the principle of conservation of energy. It is calculated by equating the kinetic energy of the object to the gravitational potential energy at Earth's surface.

Understanding escape velocity is crucial in astronomy, space science, and rocket engineering. It helps scientists design spacecraft that can leave Earth and reach satellites, the Moon, or other planets. Rockets like the Saturn V and SpaceX Falcon 9 are engineered to achieve escape velocities or orbital velocities depending on mission requirements.

In summary, the correct answer is Earth’s gravitational pull, as escape velocity is the speed needed for a rocket to overcome Earth’s gravity and enter space. This principle is a cornerstone of physics and space exploration.