  access_time 2019-01-22T22:45:06.285Z face Rohit agrawal

PDF OF GRAVITATION QUESTIONS

GRAVITATION QUESTIONS

BY – ROHIT AGRAWAL

# VIDEO SOLUTIONS OF ALL QUESTIONS

• QUES – Escape velocity from the earth 11.2 km/sec . Another planet of same mass has radius ¼ times that of earth . What is the escape velocity from this planet ?
• 11.2 km/sec
• 44.8 km/sec
• 22.4 km/sec
• 5.6 km/sec

• QUES -2 – A body  attends the height equal to the radius of the earth when projected from earth surface . The velocity of the body with which it was projected is :

(A)

(B)

(C)

(D)

• QUES -3 – An earth satellite is moving in                                                                          a circular orbit with a uniform speed v , if the gravitational force of the earth suddenly disappear , the satellite will
• Vanish into outer space
• Continue to move with velocity v in original orbit
• Fall down with increasing velocity
• Fly off tangentially from the orbit with velocity v

• QUES -4 – the maximum and minimum distance of a comet from the sun are 8 X 10 2  m and 1.6                              X 1012 m representing . If its velocity when it is nearest to the sun is 60 m/sec then what will be its velocity in m/s when it is farthest ?
• 12
• 60

(C) 112

(D) 6

• QUES -5 – the gravitational potential energy of a body at a distance r from the center of the earth is u . The force at a point :
• u/r2
• u/r
• Ur
• ur2

• QUES -6- if the spinning speed of earth is increased , then the weight of the body at the equator

(A) does not change (B)Doubles

(D)  increases

• QUES -7 – when the radius of earth reduced by 1% without changing the mass , then the acceleration due to gravity will
• Increase by 2 %
• Decreases by 1.5 %
• Increases by 1 %
• Decreases by 1 %

• QUES -8 – a particle falls from infity the earth . Its velocity on reaching the earth surface is
• 2Rg

• Rg (C) (D)

• QUES -9 – weight of a body mass M decreased by 1 % when it is raised to height h above the earth surface . If the body is taken to the depth h in a mine , then in its weight will
• Decrease by 0.5 %
• Decrease by 2 %
• Increase by 0.5 %
• Increase by 1 %

• QUES -10 – the escape velocity from the earth 11.2 km/sec . The mass of another planet is 100 times of mass of earth and its radius is 4 times the radius of earth . The velocity of the planet is                                                                               :
• 56.0 km/sec
• 280 km/sec
• 112 km/sec
• 11.2 km/sec

• QUES -11 – acceleration due to gravity of earth surface is ‘g’ ms-2 find the effective value of acceleration due to gravity at a height of 32 km from sea level : (Re = 6400 km )

(A) 0.5 g ms-2

(B)   0.99 g ms-2

(C)  1.01 g ms -2

(D) 0.90 g ms-2

• QUES -12 –near the earth surface time period of a satellite is 1.4 hrs. find its time period if its is at the distance ‘4R’ from the center of earth :

(A) 32 hrs. (B) ( 1/8 2)

• 8   2
• 16 hrs .

• QUES -13 – the mass of moon is 1% of mass of the earth . The ratio of gravitational pill of earth on moon to that of moon on earth will be :

(A) 1:1 (B) 1:10 (C) 1:100

(D) 2:1

• QUES -14 – a palnet revolve around the sun in an elliptical orbit . If vp and va are the velocities of the planet at the perigee and apogee respectively , then the eccentricity of the elliptical orbit is given by :

(A)𝑣𝑝

𝑣𝑎

(B)𝑣𝑎 −𝑣𝑝

𝑣𝑎+𝑣𝑝

(C)𝑣𝑎+𝑣𝑝

𝑣𝑎−𝑣𝑝

(D)𝑣𝑝 −𝑣𝑎

𝑣𝑝+𝑣𝑎

• QUES -15 –a communication of satellite of earth which takes 24 hrs . To complete one circular orbit eventually has to be replaced by another satellite of double mass . If the new satellite also ha s on orbital time period of 24 hrs , then what is the ratio of the radiusof the new orbit to original orbit ?

(A) 1:1

(B) 2:1

(C)   :1

(D) 1:2

• QUES -16 –when you move from equator to pole , the value of acceleration due to gravity (g) ;
• Increase
• Decrease
• Remains the same
• First increase then decrease

• QUES -17 – imagine a new planet having the same density as that of earth but it is 3 times bigger than the size . If the acceleration due to gravity on the surface of earth is g and that on the surface of the new planet :
• g’=3g
• g’=g/9
• g’=9g
• G’=27g

• QUES -18 –escape velocity for a projectile at earth surface is ve . Abody is projected from eart’s surface with velocity 2 v e . The velocity of the body when it is at infinite distance from the center of the earth is :
• Ve
• 2ve

• 2 ve

• 3  ve

• QUES -19 – for a satellite moving in an orbit around the earth , the ratio of kinetic energy to potential energy is :
• 2
• ½

• 2

(D) 1/    2

• QUES -20 – if earth revolves around the sun in an orbit of double radius of its present radius . Then the year on earth will be of –

(A) 365/4 days

(B)  365 x 2   2 𝑑𝑎𝑦𝑠

• 365/2 days
• 365 x4 days

• QUES – 21- mars has diameter approximately 0.5 of that of earth . And mass of 0.1 of that earth . The surface gravitational field strength on mars as compared of that on earth is greater by a factor of –

(A) 0.1

(B) 0.2

(C) 2.0

(D) 0.4

• QUES -22 –the change in the value of g at a height ‘h’ above the surface of the earth is same as that a depth ‘d’ . If ‘d’ and ‘h’ are much smaller than the radius of earth , then which one of the following is correct ?
• d=h
• D=2h
• D=3h/2
• D=h/2

• QUES -23 – two satellite of earth S1 and S2 are moving in the same orbit . The mass of S1 is four times the mass S2 , which one of the following statement is true /
• The kinetic energies of the two satellite are equal
• The times period of S1 is four times that of S2
• The potential energies of earth and satellite in the two cases are equal
• S1 and S 2 are moving with the same speed

• QUES -24 –the angular speed of earth is radian per sec , so that bodies on equator may appear weightless is :

(A) 1.25 x 10-3

(B) 1.56 x 10 +-3

(C) 1.25 x 10 -3

(D) 1.56

• QUES -25 – a body weight W newton the surface of the earth . Its weight at a height equal to half the radius of earth will be :
• W/2
• 2W/3
• 4W/9
• W/4

• QUES -26 – the radii of circular orbit two satellite A and B of the earth are 4R and R respectively, if the speed of satellite A and 3V , then the speed of satellite B will be ;
• 3V/2
• 3V/4
• 6V
• 12V

# VISIT ROHITAGRAWAL.CO.IN

• QUES -27 – A particle have mass M is situated at the center of a spherical shell of same mass and radius a the gravitational potential at a point situated at a/2 distance from the center , will be :
• -4GM/a
• -3GM/a
• -2GM/a
• -GM/a

• QUES -28 – The additional kinetic energy to be provided to a satellite of mass m revolving around a planet of mass M , to transfer it form a circular orbit of radius R1 to another of radius R2 (R2 >R1 ) is :

1      1

(A)  GmM(𝑅1 -𝑅2)

1      1

(B)  2GmM(𝑅1 -𝑅2)

1      1

(C) 1/2GmM(𝑅1 -𝑅2)

1      1

(D) GmM(𝑅2  -𝑅2)

1        2

• QUES -29 – A planet moving along a elliptical orbit is closet to the sun at a distance t1 and farthest away at a distance of r2 . If v1 and v2 are the linear velocities at these points respectively , then the ratio v1 /v2 is :-

(A) (r1 /r2 )2

(B) r1 /r2 (C) (r2 /r1 )2

(D)  r1 /r2

• QUES -30 – a spherical planet has mass Mp and diameter Dp A particle of mass m falling freely near the surface                                   of thie surface of this planet will experience an acceleration due to gravity equa;l to :
• GMP /DP2
• 4GMP /DP2

• 4GMP m/DP2
• GMP m/DP2

• QUES -31 – A geostationary satellite is orbiting the earth at a height of 5R above that surface of earth , R being the radius of the earth , R being the radius of the earth . The time period of another satellite                                                                 in hour at a height of 2R from the surface of the earth is :

(A) 6   2

(B) 6/   2

• 5
• 10

• QUES -32 –the height at which the weight of a body becomes 1/16th , its weight on the surface of earth (radius R) is :
• 3R
• 4R
• 5R
• 15R

• QUES -33 – A particle is thrown with escape velocity ve                                                                                from the surface of earth . Calculate its velocity at height 3R:
• 9.25Km/s
• -5.6 Km/s
• 11.2 Km/s
• 4.3 Km/s

• QUES – 34-newton’s law of gravitation is :
• Is not applicable out side the solar system
• Is used to govern the motion of satellite only
• Control the rotational motion of satellite and planet
• Control the rotational motion of electron in atoms

• QUES -35 – acceleration due to gravity at the center of earth is :
• G
• g/2
• Zero
• Infinite

• QUES -36 – if the distance between centers of earth and moon D and mass of earth is 81 times that of moon . At what distance from the center of earth gravitational field will be zero :
• D/2
• 2D/3
• 4D/5

(D) 9D/10

• QUES -37 – A particle falls on earth(i) from infinity                                                                   , (ii) from a height 10 times of radius of earth . The ratio of the velocities gained on

reaching at the earth’s surface is :

(A)   11:   10

(B)  10:    11

(C) 10:11

(D) 11:10

• QUES – 38 – the binding energy of moon is :

(A)𝐺𝑚𝑒 𝑀𝑚 /𝑟𝑒𝑚 (B)𝐺𝑚𝑒Mm /rem (C)𝐺𝑚𝑒 Mm /rem

(D) - 𝐺𝑚𝑒Mm /rem

• QUES -39 – the average radii of a orbit mercury and earth around the sun are 6 x 10 7 km and 1.5 x 108 km respectively . The ratio of their orbital speed will be :

(A)   5:   2

(B) 2: 5 (C) 2.5 :1 (D) 1:25

• QUES -40 – A body is drop by a satellite in its geo – stationary orbit :
• It will burn on entering in to the atmosphere
• it will remain in the same place with respect to earth
• It will reach earth is 24 hours
• It will perform uncertain motion

A Great Place to Start