Escape Velocity

IMPORTANT

Escape Velocity: Overview

This topic helps us in understanding that we can throw an object with such high initial speeds that it does not fall back to the earth. The mathematical proof of escape speed is also explained.

Important Questions on Escape Velocity

EASY
IMPORTANT

Two bodies each of mass M are kept fixed with a separation 2L. A particle of mass m is projected from the mid-point of the line joining their centres perpendicular to the line. The gravitational constant is G. The correct statement s is (are)

MEDIUM
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The escape velocity of a spherical planet of radius R and density ρ is V. If the radius of this planet is changed to 3R and density is changed to 3ρ, then the escape velocity of the planet will be changed to

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Velocity of escape, from earth’s surface, is _____  km s-1.

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Calculate the escape velocity of a body from the surface of the earth. (Given: G=6.67 x 10-11 Nm2/kg2, R=6400 km, g=9.8 m/s2)

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Define escape velocity. Write an expression for the escape velocity of an object from the surface of the earth.

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Gravitational acceleration on the surface of the planet is 611g, where g is the acceleration due to gravity on the surface of earth. The average mass density of the planet is 23 times that of the earth. If the escape speed on the surface of the earth is taken to be 11 km s-1, then find the escape speed on the surface of the planet (in km s-1).

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Velocity of escape is _____ times the orbital velocity of a satellite revolving very close to the surface of earth. 
(Choose from 3 (1.732) or 2 (1.414).)

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Choose the incorrect statements from the following options.

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A satellite is revolving at a height h from the surface of earth. Then the change in velocity for the satellite to escape the gravitational field of earth, is:

HARD
IMPORTANT

There are two identical starts of mass 3×1031 kg each with distance  2×1011m between them. Now a material is projected with velocity v from the midpoint of the line joining the stars. What should be the minimum value of v so that it goes out by gravitational field of the given stars?

HARD
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The ratio of accelerations due to gravity g1 : g2 on the surfaces of two planets is 5 :2 and the ratio of their respective average densities ρ1:ρ2 is 2 :1 . What is the ratio of respective escape velocities v1 :v2  from the surface of the planets?

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The escapse velocity from the Earth is 11 kms-1. The escpe velocity from a planet having twice the radius and same mean density as that of Earth is

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The escape velocity from the earth is about  11 kms-1 . The escape velocity from a planet having twice the radius and the same mean density as the earth is

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A body is projected vertically from the surface of the earth of radius 'R' with a velocity equal to half of the escape velocity. The maximum height reached by the body is

MEDIUM
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Escape velocity at surface of earth is 11.2 km/s. Escape velocity from a planet whose mass is the same as that of earth and radius 1/4 that of earth, is

MEDIUM
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The escape velocity on the surface of earth is 11.2 km/s. What would be the escape velocity on the surface of another planet of the same mass but 14 times the radius of the earth?

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The escape velocity of a body on the surface of the earth is 11.2 km/s. If the earth's mass increases to twice its present value and the radius of the earth becomes half, the escape velocity would become

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The value of escape velocity of a certain planet is 2 km/s. Then the value of orbital speed for a satellite orbiting closer to its surface is:

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There is no atmosphere on the moon because

HARD
IMPORTANT

Two spherical planets P and Q have the same uniform density ρ , masses MP and MQ , and surface areas A and 4A, respectively. A spherical planet R also has uniform density ρ and its mass is MP+MQ . The escape velocities from the planets P, Q and R, are vP , vQ , vR respectively, then