JEE Questions for Physics Gravitation Quiz 9 - MCQExams.com

At the surface of a certain planet, acceleration due to gravity is one-quarter of that on earth. If a brass ball is transported to this planet, then which one of the following statements is not correct
  • The mass of the brass ball on this planet is a quarter of its mass as measured on earth
  • The weight of the brass ball on this planet is a quarter of the weight as measured on earth
  • The brass ball has the same mass on the other planet as on earth
  • The brass ball has the same volume on the other planet as on earth
Mass of moon is 7.34 × 1022 kg . If the acceleration due to gravity on the moon is 1.4 m/s2, the radius of the moon is
(G = 6.667 × 10-11 Nm2 / kg2)
  • 0.56 × 104m
  • 1.87 × 106 m
  • 1.92 × 106 m
  • 1.01 × 108 m
What should be the velocity of earth due to rotation about its own axis so that the weight at equator become 3/5 of initial value? Radius of earth on equator is 6400 km.
  • 7.4 × 10–4 rad/sec
  • 6.7 × 10–4 rad/sec
  • 7.8 × 10–4 rad/sec
  • 8.7 × 10–4 rad/sec
If radius of earth is R, then the height \'h\' at which value of \'g\' becomes one-fourth is
  • R/4
  • 3R/4
  • R
  • R/8
Two planets of radii in the ratio 2 : 3 are made from the material of density in the ratio 3 : 2. Then, the ratio of acceleration due to gravity g1/g2 at the surface of the two planets will be
  • 1
  • 2.25
  • 4/9
  • 0.12
Assume that the acceleration due to gravity on the surface of the moon is 0.2 times the acceleration due to gravity on the surface of the earth. If Re is the maximum range of a projectile on the earth\'s surface, what is the maximum range on the surface of the moon for the same velocity of projection ?
  • 0.2 Re
  • 2 Re
  • 0.5 Re
  • 5 Re
What will be the acceleration due to gravity at height h if h >> R. Where R is radius of earth and g is acceleration due to gravity on the surface of earth ?

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  • 2)
    Physics-Gravitation-74480.png

  • Physics-Gravitation-74481.png

  • Physics-Gravitation-74482.png
A research satellite of mass 200 kg circles the earth in an orbit of average radius 3R/2 where R is the radius of the earth. Assuming the gravitational pull on a mass of 1 kg on the earth\'s surface to be 10 N, the pull on the satellite will be
  • 880 N
  • 889 N
  • 890 N
  • 892 N
The value of g decreases inside the surface of earth because
  • A force of upward attraction is applied by the shell of earth above
  • The shell of earth above exerts no net force
  • The distance from the centre of the earth decreases
  • The density of the material at the centre of the earth is very small
The value of g on the surface of earth is smallest at the equator because
  • The centripetal force is maximum at equator
  • The centripetal force is least at equator
  • The angular speed of earth of maximum at equator
  • The angular speed of earth is least at equator
An astronaut on a strange planet finds that acceleration due to gravity is twice as that on the surface of earth. Which of the following could explain this ?
  • Both the mass and radius of the planet are half as that of earth
  • Radius of the planet is half as that of earth, but the mass is the same as that of earth
  • Both the mass and radius of the planet are twice as that of earth
  • Mass of the planet is half as that of earth, but radius is same as that of earth
Assuming that the earth is a sphere of radius RE with uniform density, the distance from its centre at which the acceleration due to gravity is equal to g/3 [ g is the acceleration due to gravity on the surface of earth) is

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    Physics-Gravitation-74488.png

  • Physics-Gravitation-74489.png

  • Physics-Gravitation-74490.png
A planet in a distant solar system is 10 times more massive than the earth and its radius is 10 times smaller. Given that the escape velocity from the earth is 11 km s-1, the escape velocity from the surface of the planet would be
  • 11 km s-1
  • 110 km s-1
  • 0.11 km s-1
  • 1.1 km s-1
In a gravitational field , at a point where the gravitational potential is zero
  • The gravitational field is necessarily zero
  • The gravitational field is not necessarily zero
  • Nothing can be said definitely about the gravitational field
  • None of the above
The gravitational field due to a mass distribution is E = K/x3 in the x-direction. (K is a constant). Taking the gravitational potential to be zero at infinity, its value at a distance x is
  • K/x
  • K/2x
  • K/x2
  • K/2x2
The mass of the earth is 6.00 × 1024 kg and that of the moon is 7.40 × 1022 kg. The constant of gravitation G = 6.67 × 10–11 N – m2/kg2. The potential energy of the system is –7.79 × 1028 joules. The mean distance between the earth and moon is
  • 3.80 × 108 m
  • 3.37 × 106 m
  • 7.60 × 104 m
  • 1.90 × 102 m
The escape velocity from earth is ves. A body is projected with velocity 2ves with what constant velocity will it move in the inter planetary space
  • ves
  • 3ves
  • √3ves
  • √5ves
If mass of earth is M, radius is R and gravitational constant is G, then work done to take 1 kg mass from earth surface to infinity will be

  • Physics-Gravitation-74496.png
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    Physics-Gravitation-74497.png

  • Physics-Gravitation-74498.png

  • Physics-Gravitation-74499.png
There are two bodies of masses 100 kg and 10000 kg separated by a distance 1 m. At what distance from the smaller body, the intensity of gravitational field will be zero?

  • Physics-Gravitation-74501.png
  • 2)
    Physics-Gravitation-74502.png

  • Physics-Gravitation-74503.png

  • Physics-Gravitation-74504.png
Energy required to move a body of mass m from an orbit of radius 2R to 3R is
  • GMm/12R2
  • GMm/3R2
  • GMm/8R
  • GMm/6R
Gas escapes from the surface of a planet because it acquires an escape velocity. The escape velocity will depend on which of the following factors :
I. Mass of the planet
II. Mass of the particle escaping
III. Temperature of the planet
IV. Radius of the planet
Select the correct answer from the codes given below :
  • I and II
  • II and IV
  • I and IV
  • I,III and IV
Infinite number of masses, each 1 kg, are placed along the x axis at x = ± 1 m, ± 2m, ± 4m, ± 8m, ± 16m... The magnitude of the resultant gravitational potential in terms of gravitational constant G at the origin (x = O) is
  • G/2
  • G
  • 2G
  • 4G
The escape velocity of a sphere of mass m from earth having mass M and radius R is given by

  • Physics-Gravitation-74509.png
  • 2)
    Physics-Gravitation-74510.png

  • Physics-Gravitation-74511.png

  • Physics-Gravitation-74512.png
A missile is launched with a velocity less than the escape velocity. The sum of its kinetic and potential energy is
  • Positive
  • Negative
  • Zero
  • May be positive or negative depending upon its initial velocity
Escape velocity on a planet is ve.If radius of the planet remains same and mass becomes 4 times, the escape velocity becomes
  • ve
  • 1/2 ve
  • 4ve
  • 2ve
The escape velocity of a body from earth\'s surface is ve. The escape velocity of the same body from a height equal to 7R from earth\'s surface will be

  • Physics-Gravitation-74514.png
  • 2)
    Physics-Gravitation-74515.png

  • Physics-Gravitation-74516.png

  • Physics-Gravitation-74517.png
How much energy will be necessary for making a body of 500 kg escape from the earth ?
[g = 9.8 m/s2, radius of earth = 6.4 × 106 m]
  • About 9.8 × 106 J
  • About 6.4 × 108 J
  • About 3.1 × 1010 J
  • About 27.4 × 1012 J
An artificial satellite is revolving round the earth in a circular orbit. Its velocity is half the escape velocity. Its height from earth\'s surface is
  • 6400 km
  • 12800 km
  • 3200 km
  • 1600 km
There are two planets. The ratio of radius of the two planets is K but ratio of acceleration due to gravity of both planets is g. What will be the ratio of their escape velocity ?
  • (kg)1/2
  • (kg)–1/2
  • (kg)2
  • (kg)–2
The angular velocity of rotation of star (of mass M and radius R) at which the matter start to escape from its equator will be

  • Physics-Gravitation-74522.png
  • 2)
    Physics-Gravitation-74523.png

  • Physics-Gravitation-74524.png

  • Physics-Gravitation-74525.png
Four particles each of mass M, are located at the vertices of a square with side L. The gravitational potential due to this at the centre of the square is

  • Physics-Gravitation-74527.png
  • 2)
    Physics-Gravitation-74528.png
  • zero

  • Physics-Gravitation-74529.png
A mass of 6 × 1024 kg is to be compressed in a sphere in such a way that the escape velocity from the sphere is 3 × 108 m/s. Radius of the sphere should be
(G = 6.67 × 10–11 N – m2/kg2)
  • 9 km
  • 9 m
  • 9 cm
  • 9 mm
The radius of a planet is 1/4 of earth\'s radius and its acceleration due to gravity is double that of earth\'s acceleration due to gravity. How many times will the escape velocity at the planet\'s surface be as compared to its value on earth\'s surface ?

  • Physics-Gravitation-74535.png
  • 2)
    Physics-Gravitation-74536.png

  • Physics-Gravitation-74537.png
  • 2
The escape velocity for a body projected vertically upwards from the surface of earth is 11 km/s. If the body is projected at an angle of 45o with the vertical, the escape velocity will be

  • Physics-Gravitation-74539.png
  • 2)
    Physics-Gravitation-74540.png
  • 22 km/s
  • 11 km/s
The acceleration due to gravity on a planet is same as that on earth and its radius is four times that of earth. What will be the value of escape velocity on that planet if it is ve on earth ?
  • ve
  • 2ve
  • 4ve
  • ve/2
The change in the gravitational potential energy when a body mass m is raised to a height nR above the surface of the earth is (here R is the radius of the earth)

  • Physics-Gravitation-74542.png
  • 2)
    Physics-Gravitation-74543.png
  • nmgR

  • Physics-Gravitation-74544.png
The total energy of a circularly orbiting satellite is
  • Twice the kinetic energy of the satellite
  • Half the kinetic energy of the satellite
  • Twice the potential energy of the satellite
  • Equal to the potential energy of the satellite
  • Half the potential energy of the satellite
Two bodies of masses m and 4m are placed at a distance r. The gravitational potential at a point on the line joining them where the gravitational field is zero is
  • zero
  • 2)
    Physics-Gravitation-74547.png

  • Physics-Gravitation-74548.png

  • Physics-Gravitation-74549.png
A body is projected with a velocity of 2 × 11.2 kms–1 from the surface of earth. The velocity of the body when it escapes the gravitational pull of earth is

  • Physics-Gravitation-74551.png
  • 2)
    Physics-Gravitation-74552.png

  • Physics-Gravitation-74553.png

  • Physics-Gravitation-74554.png
If the escape velocity of a planet is 3 times that of the earth and its radius is 4 times that of the earth, then the mass of the planet is (Mass of the earth = 6 × 1024 kg )
  • 1.62 × 1022 kg
  • 0.72 × 1022 kg
  • 2.16 × 1026 kg
  • 1.22 × 1022 kg
The mass of a spaceship is 1000 kg. It is to be launched from the earth\'s surface out into free space. The value of \'g\' and \'R\' (radius of earth) are 10 m/s2 and 6400 km respectively. The required energy for this work will be
  • 6.4 × 1011 J
  • 6.4 × 108 J
  • 6.4 × 109 J
  • 6.4 × 1010 J
If r represents the radius of the orbit of a satellite of mass m moving around a planet of mass M, the velocity of the satellite is given by

  • Physics-Gravitation-74558.png
  • 2)
    Physics-Gravitation-74559.png

  • Physics-Gravitation-74560.png

  • Physics-Gravitation-74561.png
Select the correct statement from the following
  • The orbital velocity of a satellite increases with the radius of the orbit
  • Escape velocity of a particle from the surface of the earth depends on the speed with which it is fired
  • The time period of a satellite does not depend on the radius of the orbit
  • The orbital velocity is inversely proportional to the square root of the radius of the orbit
An earth satellite of mass m revolves in a circular orbit at a height h from the surface of the earth. R is the radius of the earth and g is acceleration due to gravity at the surface of the earth. The velocity of the satellite in the orbit is given by

  • Physics-Gravitation-74563.png
  • 2)
    Physics-Gravitation-74564.png

  • Physics-Gravitation-74565.png

  • Physics-Gravitation-74566.png
Two satellites of masses m1 and m2 (m1 > m2) are revolving round the earth in circular orbits of radius r1 and r2(r1>r2) respectively. Which of the following statements is true regarding their speeds v1 and v2 ?
  • v1 = v2
  • v1 < v2
  • v1 > v2

  • Physics-Gravitation-74568.png
A satellite which is geostationary in a particular orbit is taken to another orbit. Its distance from the centre of earth in new orbit is 2 times that of the earlier orbit. The time period in the second orbit is
  • 4.8 hr
  • 48√2 hr
  • 24 hr
  • 24√2 hr
The time period of a geostationary satellite at a height 36000 km is 24 hr. A spy satellite orbits very close to earth surface (R = 6400 km). What will be its time period ?
  • 4 hrs
  • 1 hrs
  • 2 hrs
  • 1.5 hrs
The period of a satellite in a circular orbit around a planet is independent of
  • The mass of the planet
  • The radius of the planet
  • The mass of the satellite
  • All the three parameters (1), (and (3)
The relay satellite transmits the T.V. programme continuously from one part of the world to another because its
  • Period is greater than the period of rotation of the earth
  • Period is less than the period of rotation of the earth about its axis
  • Period has no relation with the period of the earth about its axis
  • Period is equal to the period of rotation of the earth about its axis
A geostationary satellite
  • Revolves about the polar axis
  • Has a time period less than that of the near earth satellite
  • Moves faster than a near earth satellite
  • Is stationary in the space
0:0:1


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