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The gravitational potential energy is maximum at

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Important Questions on Gravitation

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A spherically symmetric gravitational system of particles has mass density ρ=ρ0 for rR0 for r>R where, ρ0 is a constant. A test mass can undergo circular motion under the influence of the gravitational field of particles. Its speed v as a function of distance r(0<r<) from the centre of the system is represented by

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The change in potential energy when a body of mass m is raised to a height nR from the earth's surface is (R=radius of earth),
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A particle of mass M is situated at the centre of a spherical shell of same mass and radius a. The magnitude of the gravitational potential at a point situated at a2 distance from the centre, will be 
 
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A mass 'm' on the surface of the Earth is shifted to a target equal to the radius of the Earth. If 'R' is the radius and 'M' is the mass of the Earth, then work done in this process is:
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A uniform cable of mass M and length L is placed on a horizontal surface such that its 1nth part is hanging below the edge of the surface. To lift the hanging part of the cable upto the surface, the work done should be:
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A particle falls towards earth from infinity. Its velocity on reaching the earth would be:
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The mass density of a planet of radius R varies with the distance r from its centre as ρ(r)=ρ01-r2R2, then the gravitational field is maximum at:
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A rocket is launched vertically from the surface of the earth with an initial velocity equal to one-third of the escape velocity. If we ignore the atmospheric resistance, what will be the maximum height attained by the rocket?
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Consider two solid spheres of radii R1=1 m,R2=2 m and masses M1 and M2, respectively. The gravitational field due to sphere 1 and 2 are shown. The value of M1M2 is:

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A satellite of massM  is launched vertically upwards with an initial speed u from the surface of the earth. After it reaches height R ( R= radius of the earth), it ejects a rocket of mass M10 so that subsequently the satellite moves in a circular orbit. The kinetic energy of the rocket is ( G is the gravitational constant; Me is the mass of the earth):
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A tunnel has been dug through the centre of the earth and a ball is released in it. It will reach the other end of the tunnel after about
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From a solid sphere of mass M and radius R, a spherical portion of radius R2 is removed as shown in the figure. Taking gravitational potential V=0 at r=, the potential at the centre of the cavity thus formed is (G=gravitational constant)

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A solid sphere of radius R gravitationally attracts a particle placed at 3R from its centre with a force F1. Now a spherical cavity of radius R2 is made in the sphere (as shown in figure) and the force becomes F2. The value of F1:F2 is:

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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
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Find the gravitational force of attraction between the ring and sphere as shown in the diagram, where the plane of the ring is perpendicular to the line joining the centres. If 8R is the distance between the centres of a ring (of mass m) and a sphere (mass M) where both have equal radius R

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A particle of mass m is projected with a velocity v=kVe (k<1) from the surface of the earth (Ve= escape velocity). The maximum height above the surface reached by the particle is___
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Inside a uniform spherical shell :

(a) The gravitational field is zero.

(b) The gravitational potential is zero.

(c) The gravitational field is the same everywhere.

(d) The gravitation potential is the same everywhere.

(e) All the above.

Choose the most appropriate answer from the options given below:

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Consider a spherical gaseous cloud of mass density ρr in free space where r is the radial distance from its center. The gaseous cloud is made of particles of equal mass m moving in circular orbits about the common center with the same kinetic energy K . The force acting on the particles is their mutual gravitational force. If ρr is constant in time, the particle number density nr=ρr/m is: [ G is universal gravitational constant]
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A rocket has to be launched from earth in such a way that it never returns. If E is the minimum energy delivered by the rocket launcher, what should be the minimum energy that the launcher should have, if the same rocket is to be launched from the surface of the moon? Assume that the density of the earth and the moon are equal and that the earth's volume is 64 times the volume of the moon.
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Which of the following most closely depicts the correct variation of the gravitation potential, V(r) with distance r due to a large planet of radius R and uniform mass density? (figures are not drawn to scale)