HelpContactFor teachers and institutes
>_StemPy Lab
Mock TestsClasses

>_StemPy Lab

Learn. Solve. Code the solutions. Test yourself.

Live examsFree mock exams, timed and rankedEveryone starts together, and your score and rank come the moment it ends.See the exams →

Learn

  • Physics
  • Chemistry
  • Mathematics
  • Biology
  • Python Programming
  • Statistics & Data Science
  • Classes
  • Groups

Practice

  • Problems
  • Quizzes
  • Mock Tests
  • Prepare for an Exam
  • Question Sets
  • Exams
  • Certificates
  • Python Labs
  • AI Practice Generator
  • Student-Created Tests

Community

  • Discussions
  • Resources
  • Notes
  • Glossary
  • Blog

Account

  • Log in
© 2026 senLearn. All rights reserved.HelpAboutContactPrivacy PolicyTerms of UseRefund Policy
  1. Glossary
  2. /Physics
  3. /Escape Speed

What is Escape Speed?

In short

Escape speed is the minimum speed with which an object must be thrown from the surface of a planet so that it never falls back, ignoring air resistance. For the Earth it is about 11.2 km/s11.2\ \text{km/s}11.2 km/s.

In simple words

It is given by ve=2GMR=2gRv_e = \sqrt{\dfrac{2GM}{R}} = \sqrt{2gR}ve​=R2GM​​=2gR​, where MMM and RRR are the mass and radius of the planet. It does not depend on the mass of the object that is thrown, and it does not depend on the direction of the throw. This is why the Moon, with a small MMM and RRR, has almost no atmosphere: its escape speed is only 2.4 km/s2.4\ \text{km/s}2.4 km/s.

Example

With g=9.8 m/s2g = 9.8\ \text{m/s}^2g=9.8 m/s2 and R=6.4×106 mR = 6.4 \times 10^{6}\ \text{m}R=6.4×106 m, ve=2×9.8 m/s2×6.4×106 m=1.12×104 m/sv_e = \sqrt{2 \times 9.8\ \text{m/s}^2 \times 6.4 \times 10^{6}\ \text{m}} = 1.12 \times 10^{4}\ \text{m/s}ve​=2×9.8 m/s2×6.4×106 m​=1.12×104 m/s.

Also searched as: escape velocity.

Learn it properly

  • Lessons on this topic
  • Practise problems
  • Test yourself

Related terms

  • Acceleration Due to Gravity (g)
  • Kinetic Energy and Potential Energy

← All glossary terms

Learn it in

  1. The Law of GravitationClass 9 to 10
  2. Mass, Weight and Free FallClass 9 to 10
  3. Kepler's Laws and Universal GravitationClass 11 to 12
All lessons on this topic →

Practise

  1. The Earth's mass is 81 times the Moon's, and the distance between their centres is 60RE…Hard
  2. A satellite of mass 500 kg moves in a circular orbit of radius 7000 km round the Earth…
Hard
  • Two stars, A of mass 2M and B of mass M, where M = 1.0 × 10³⁰ kg, move in circular…Advanced
  • A planet is a uniform sphere of radius R = 3200 km and centre O…Advanced
    • All problems on this topic →

    Quick questions

    1. A satellite moves in a circular orbit of radius r round a planet. Its rocket fires for a…Advanced
    2. A satellite moves eastwards in a circular orbit of radius 2R in the plane of the…Advanced
    3. Treat the Earth as a uniform sphere of radius R = 6400 km, with g = 10 m/s² at its…Hard

    More Physics terms

    1. Weight and Mass
    2. Acceleration
    3. Adiabatic Process
    4. Amplitude
    5. Angle of Incidence
    6. Angle of Reflection
    All Physics terms →

    Preparing for an exam?

    Pick your exam to see its syllabus, where you stand in each unit and what to practise next.

    See exam preparation