Are used for environmental studies

Are widely used for telecommunication

Go around the Earth in a East-West direction

Have time - period of rotation of 24 hours

Are used for environmental studies

EASY

Earn 100

Polar satellites

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Important Questions on Gravitation

MEDIUM

Physics>Mechanics>Gravitation>Satellites

Define binding energy and obtain an expression for binding energy of a satellite revolving in a circular orbit round the earth.

EASY

Physics>Mechanics>Gravitation>Satellites

A satellite is launched to a distance

r

from the centre of the earth to have a circular orbit around the earth. Its orbital velocity to maintain this orbit is (mass of the earth as

M_{E}

)

EASY

Physics>Mechanics>Gravitation>Satellites

A person jumps from the

5^{th}

storey of a building with load on his head. The weight experienced by him before reaching the earth will be

MEDIUM

Physics>Mechanics>Gravitation>Satellites

Two satellites,

A

and

B

, have masses

m

and

2 m

respectively.

A

is in a circular orbit of radius

R

and

B

is in a circular orbit of radius

2 R

around the earth. The ratio of their kinetic energies,

\frac{K_{A}}{K_{B}}

is:

MEDIUM

Physics>Mechanics>Gravitation>Satellites

A spaceship orbits around a planet at a height of

20 k m

from its surface. Assuming that only gravitational field of the planet acts on the spaceship, what will be the number of complete revolutions made by the spaceship in

24

hours around the planet?
[Given: Mass of planet

= 8 \times 10^{22} k g

,
Radius of planet

= 2 \times 10^{6} m,

Gravitational constant

G = 6.67 \times 10^{- 11} N m^{2} / k g^{2}

]

HARD

Physics>Mechanics>Gravitation>Satellites

Two stars of masses

3 \times 10^{31} kg

each, and at distance

2 \times 10^{11} m

rotate in a plane about their common centre of mass

O .

A meteorite passes through

O

moving perpendicular to the star's rotation plane. In order to escape from the gravitational field of this double star, the minimum speed that meteorite should have at

O

is ( Take Gravitational constant

G = 6.67 \times 10^{- 11} N m^{2} {kg}^{- 2}

)

MEDIUM

Physics>Mechanics>Gravitation>Satellites

Two satellites

A

and

B

are revolving with critical velocities

v_{A}

and

v_{B}

around the earth, in circular orbits of radii

R

and

2 R

respectively. The ratio

\frac{v_{A}}{v_{B}}

EASY

Physics>Mechanics>Gravitation>Satellites

A satellite S is moving in an elliptical orbit around the earth. The mass of the satellite is very small compared to the mass of the earth. Then,

HARD

Physics>Mechanics>Gravitation>Satellites

The mass density of a spherical galaxy varies as

\frac{K}{r}

over a large distance

r

from its center. In that region, a small star is in a circular orbit of radius

R

. Then the period of revolution,

T

depends on

R

as:

EASY

Physics>Mechanics>Gravitation>Satellites

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:

MEDIUM

Physics>Mechanics>Gravitation>Satellites

The minimum number of geostationary satellites required for uninterrupted global coverage is

MEDIUM

Physics>Mechanics>Gravitation>Satellites

A satellite is revolving in a circular orbit at a height

h

from the earth's surface (radius of earth

R

;

h << R

). The minimum increase in its orbital velocity required, so that the satellite could escape from the earth's gravitational field, is close to (Neglect the effect of atmosphere.)

MEDIUM

Physics>Mechanics>Gravitation>Satellites

The energy required to take a satellite to a height

h

above the Earth surface (radius of Earth

= 6.4 \times 10^{3} km

) is

E_{1}

, and the kinetic energy required for the satellite to be in a circular orbit at this height is

E_{2} .

The value of

h

for which

E_{1}

and

E_{2}

are equal, is

EASY

Physics>Mechanics>Gravitation>Satellites

Which satellite is used for geographical survey?

EASY

Physics>Mechanics>Gravitation>Satellites

A remote-sensing satellite of earth revolves in a circular orbit at a height of

0.25 \times 10^{6}

m above the surface of earth. If earth's radius is

6.38 \times 10^{6} m

and

g = 9.8 m s^{- 2}

, then the orbital speed of the satellite is:

EASY

Physics>Mechanics>Gravitation>Satellites

The ratio of the binding energy of a satellite at rest on earth's surface to the binding energy of a satellite of same mass revolving around the earth at a height

h

above the earth's surface is

(R

= radius of the earth

)

MEDIUM

Physics>Mechanics>Gravitation>Satellites

What is the minimum energy required to launch a satellite of mass

m

from the surface of a planet of mass

M

and radius

R

in a circular orbit at an altitude of

2R

EASY

Physics>Mechanics>Gravitation>Satellites

A planet is moving in a circular orbit. It completes

2

revolutions in

360 days

. What is its angular frequency?

HARD

Physics>Mechanics>Gravitation>Satellites

A test particle is moving in a circular orbit in the gravitational field produced by a mass density

ρ (r) = \frac{K}{r^{2}} .

Identify the current relation between the radius

R

of the particle’s orbit and its period

T :

EASY

Physics>Mechanics>Gravitation>Satellites

The relative uncertainty in the period of a satellite orbiting around the earth is

10^{- 2}

. If the relative uncertainty in the radius of the orbit is negligible, the relative uncertainty in the mass of the earth is:

Polar satellites

Important Questions on Gravitation

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