In Physics, Escape Velocity is the minimum velocity that is sufficient for a body to escape from the gravitational pull of a planet. The Escape Velocity of the same objects might be different on different planets & moons.
The Escape Velocity of an object on the earth is greater than the escape velocity of the same object on the moon.
⇒ The Escape Velocity or Escape Speed of an object on the Earth is around 11.2 km/s.
⇒ The Escape Velocity of an object on the Moon is around 2.3 km/s.
Formula For Escape Velocity (Earth):
vminimum = (2GME/RE)½
vminimum: is the minimum speed required for an object to reach infinity (i.e. escape from the earth).
G: Universal Gravitational Constant (Value of G = 6.67 × 10-11 Newtons kg-2 m2)
ME: Mass of the Earth
RE: Radius of the Earth
Another Formula For Escape Velocity (Earth):
vminimum = (2gRE)1/2
g: Acceleration due to gravity
Rest symbols have their usual meaning.
Some questions on Escape Velocity:
Question: What is the SI unit of Escape Speed?
Answer: The Escape Velocity or Escape Speed of an object on the Earth is around 11.2 km/s.
Question: Determine the escape velocity of a planet if its radius is 7000 Km and mass is 107 kg.
We know that vminimum = (2GM/R)½
G = 6.67 × 10-11 Newtons kg-2 m2
M = 107 kg.
R = 7000 km = 7000 x 1000 = 7 x 106.
By putting these values in the formula you can calculate the Escape Velocity of the object.