HARD

Earn 100

Assertion $(A)$ : Earth has atmosphere and moon doesn't.

Reason $(R)$ : Escape speed on moon is less than that of Earth.

44.12% studentsanswered this correctly

Important Questions on Gravitation

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

A space station is at a height equal to the radius of the Earth. If '

V_{E}

' is the escape velocity on the surface of the Earth, the same on the space station is _____

V_{E}

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

Directions: Each of the following sentences in this section has a blank space and four words or group of words given after the sentence. Select the word or group of words you consider most appropriate for the blank space and indicate your response on the Answer Sheet accordingly.

Every rash driver becomes a ____ killer.

EASY

Physics>Mechanics>Gravitation>Escape Velocity

A body is projected vertically upwards from earth's surface with velocity

2 v_{e},

where

v_{e}

is escape velocity from earth's surface. The velocity when body escapes the gravitational pull is

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

Consider two spherical planets $A$ and $B$ with radii

R_{A}

and

R_{B}

respectively. If

R_{A} = 2 R_{B}

and the escape velocities at the two planets

V_{escape}^{A}

and

V_{escape}^{B}

are equal, then the ratio of densities of $A$ and $B$,

ρ_{A} : ρ_{B}

is (consider $A$ and $B$ to be uniformly dense)

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

A black hole is an object whose gravitational field is so strong that even light cannot escape from it. To what approximate radius would earth

(m a s s = 5.98 \times 10^{24} k g)

have to be compressed to be a black hole?

HARD

Physics>Mechanics>Gravitation>Escape Velocity

Given below are two statements : one is labelled as Assertion $A$ and the other is labelled as Reason $R$ .

Assertion $A$ : The escape velocities of planet $A$ and $B$ are same. But $A$ and $B$ are of unequal mass.

Reason $R$ : The product of their mass and radius must be same. $M_{1} R_{1} = M_{2} R_{2}$ In the light of the above statements, choose the most appropriate answer from the options given below :

EASY

Physics>Mechanics>Gravitation>Escape Velocity

If the moon is to escape from the gravitational field of the earth forever, it will require a velocity ___ .

EASY

Physics>Mechanics>Gravitation>Escape Velocity

The velocity of escape on a planet whose radius is

1.7 \times 10^{6} m

and acceleration due to gravity is

1.7 m / s^{2}

EASY

Physics>Mechanics>Gravitation>Escape Velocity

Two sentences are given below and you are required to find the correct sentence which combines both the sentences.

Which is the correct combination of the given two sentences?

He is too tired. He could not stand.

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

Planet

A

has mass

M

and radius

R .

Planet

B

has half the mass and half the radius of Planet

A .

If the escape velocities from the Planets

A

and

B

are

v_{A}

and

v_{B},

respectively, then

\frac{v_{A}}{v_{B}} = \frac{n}{4} .

The value of

n

is:

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

In the following sentence, a blank space with four options is given. Select whichever preposition or determiner you consider the most appropriate for the blank space.

These are the good rules to live _____.

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

A satellite is moving with a constant speed

v

in circular orbit around the earth. An object of mass 'm' is ejected from the satellite such that it just escapes from the gravitational pull of the earth. At the time of ejection, the kinetic energy of the object is:

HARD

Physics>Mechanics>Gravitation>Escape Velocity

Consider a star of one solar mass. If only light can escape from the surface of the star, then the ratio of the radius of the star to that of the sun is(consider the star to be spherical and uniformly dense. Escape velocity on the surface of the sun is approximately

600 km s^{- 1}

, speed of light

= 3 \times 10^{8} m s^{- 1}

EASY

Physics>Mechanics>Gravitation>Escape Velocity

If a projectile has a velocity greater than the escape velocity, which trajectory will it follow?

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

A spherically uniform planet of $mass 8 \times 10^{24} kg$ and or radius $6 \times 10^{6} m$ is orbiting around the Sun. The escape velocity for the planet is close to (Take, $G = 6 \times 10^{- 11} N - m^{2} / {kg}^{2})$

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

The escape velocity from the Earth's surface is

v

. The escape velocity from the surface of another planet having a radius four times that of Earth and the same mass density is:

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

What should be the closest approximate radius of a celestial body twice as massive as the sun so that escape speed from the celestial body is equal to the speed of light? (The mass of sun is

2 \times 10^{30} kg

, speed of light

3 \times 10^{8} m s^{- 1}

, and universal gravitational constant

G = 7 \times 10^{- 11} N m^{2} {Kg}^{- 2}

)

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

Two planets have masses

M

and

16 M

and their radii are a and

2 a

, respectively. The separation between the centres of the planets is

10 a

. A body of mass

m

is fired from the surface of the larger planet towards the smaller planet along the line joining their centres. For the body to be able to reach at the surface of smaller planet, the minimum firing speed needed is :

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

A rocket is launched normal to the surface of the Earth, away from the Sun, along the line joining the Sun and the Earth. The Sun is

3 \times 10^{5}

times heavier than the Earth and is at a distance

2.5 \times 10^{4}

times larger than the radius of the Earth. The escape velocity from Earth's gravitational field is

v_{e} = 11.2 km s^{- 1}

. The minimum initial velocity

(v_{s})

required for the rocket to be able to leave the Sun-Earth system is closest to

(Ignore the rotation and revolution of the Earth and the presence of any other planet)

MEDIUM

Physics>Mechanics>Gravitation>Escape Velocity

The ratio of escape velocity at earth

(v_{e})

to the escape velocity at a planet

(v_{p})

whose radius and mean density are twice as that of earth is:

Assertion (A): Earth has atmosphere and moon doesn't. Reason (R): Escape speed on moon is less than that of Earth.

Important Questions on Gravitation

Learn and Prepare for any exam you want !

Assertion $(A)$ : Earth has atmosphere and moon doesn't.

Reason $(R)$ : Escape speed on moon is less than that of Earth.