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JEE PHYSICS MCQ: GRAVITATION

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A body is moving in a low circular orbit about a planet of mass

M

and radius

R

. The radius of the orbit can be taken to be

R

itself. Then, the ratio of the speed of this body in the orbit to the escape velocity from the planet is

View answer and explanation

Correct option: B

\frac{1}{{\sqrt 2 }}

Option B (

\frac{1}{{\sqrt 2 }}

) is correct because the ratio of orbital speed to escape velocity is always

\frac{1}{{\sqrt 2 }}

for a circular orbit at the planet's surface.

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The escape velocity for a body projected vertically upwards from the surface of the earth is

11.2\mathrm{\;\;km}{\mathrm{s}^{ - 1}}

. If the body is projected in a direction making an angle of

{45^0}

with the vertical, the escape velocity will be The escape velocity of a body projected from the surface of earth is

v_e

. If the body is projected at an angle

\theta

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