MCQ Detailed View

Every planet has a gravitational force that pulls objects toward its center. To escape this force completely and travel away from the planet without falling back, an object must reach a minimum speed known as escape velocity. For Earth, this speed is approximately 11.2 kilometers per second, which is equal to 7 miles per second.Escape velocity is determined by the mass of the Earth and its radius. It can be calculated using the formula:

ve=2GMRv_e = \sqrt{\frac{2GM}{R}}ve=R2GM

Where:

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  G = Gravitational constant

  
  


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  M = Mass of Earth

  
  


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  R = Radius of Earth

  
  

When an object is thrown or launched at this speed, it gains enough kinetic energy to overcome the gravitational potential energy of the Earth. This means that the object will not return to the surface and can travel into space.

If the object is launched with a velocity less than escape velocity, gravity will pull it back, causing it to eventually fall back to Earth. Rockets use this principle but achieve escape by continuous thrust rather than a single throw, making it more energy-efficient.

The values 25 miles/sec, 60 miles/sec, and 10 miles/sec are incorrect for Earth. The actual escape velocity of 7 miles/sec is the minimum speed needed to permanently leave Earth's gravitational influence, neglecting air resistance and other forces.

This topic belongs to Physics, specifically under mechanics and gravitational physics, as it explains the relationship between mass, gravitational force, and motion. Understanding escape velocity is fundamental in space science, satellite launching, and astrophysics.