EASY
Earn 100

If V is the gravitational potential due to sphere of uniform density on its surface, then its value at the centre of sphere will be:

68.97% studentsanswered this correctly

Important Questions on Gravitation

MEDIUM
A body of mass m is moving in a circular orbit of radius R about a planet of mass M. At some instant, it splits into two equal masses. The first mass moves in a circular orbit of radius R2 . And the other mass, in a circular orbit of radius 3R2. The difference between the final and the initial total energies is
MEDIUM

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:

EASY
A uniform solid sphere of radius R produces a gravitational acceleration of ao on its surface. The distance of the point from the centre of the sphere where the gravitational acceleration becomes ao4 is,
MEDIUM
Two particles of identical mass are moving in circular orbits under a potential given by Vr=Kr-n, where K is a constant. If the radii of their orbits are r1, r2 and their speeds are v1, v2 respectively, then
HARD
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:
MEDIUM
A planet is orbiting the sun in an elliptical orbit. Let U denote the potential energy and K denote the kinetic energy of the planet at an arbitrary point on the orbit. Choose the correct statement-
MEDIUM
A mass of 50 kg is placed at the center of a uniform spherical shell of mass 100 kg and radius 50 m. If the gravitational potential at a point, 25 m from the center is V kg m-1. The value of V is:
MEDIUM
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:
MEDIUM

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:

Question Image

MEDIUM

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

Question Image

MEDIUM
An object is propelled vertically to a maximum height of, 4R from the surface of a planet of radius, R and mass M. The speed of object when it returns to the surface of the planet is
MEDIUM

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:

Question Image

EASY
The gravitational field in a region is given by g=5i^+12j^ N kg-1. The change in the gravitational potential energy of a particle of mass 2 kg when it is taken from the origin to a point 7 m,-3 m is
HARD

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)

Question Image

MEDIUM
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.
MEDIUM
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),
HARD
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):
MEDIUM
A rocket is fired from the earth to the moon. The distance between the earth and the moon is r and the mass of the earth is 81 times the mass of the moon. The gravitational force on the rocket will be zero when its distance from the moon is,
HARD
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]
EASY
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)