HARD
Earn 100

Determine the average density of the planet for which the length of day is 6 hrs. When we weigh a body using spring balance at its equator, the scale shows weight 10% less weight than that at the pole. Fill ρ104 in kg m-3 in OMR sheet.

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Important Questions on Gravitation

MEDIUM

In the reported figure of earth, the value of acceleration due to gravity is same at point A and C but it is smaller than that of its value at point B (surface of the earth). The value of OA:AB will be x:5. The value of x is

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HARD
The ratio of accelerations due to gravity g1:g2 on the surfaces of two planets is 5: 2 and the ratio of their respective average densities ρ1:ρ2 is 2: 1 .What is the ratio of respective escape velocities v1:v2 from the surface of the planets?
EASY
The gravitational field strength at the surface of a certain planet is g . Which of the following is the gravitational field strength at the surface of a planet with twice the radius and twice the mass?
MEDIUM
The earth's mass is 80 times that of moon and their diameters are 1600 km and 800 km, respectively. If g is the value of acceleration due to gravity on earth, what is its value on moon?
HARD
A spherical body of radius R consists of a fluid of constant density and is in equilibrium under its own gravity. If P(r) is the pressure at r(r<R) , then the correct option(s) is (are)
HARD
Consider a planet in some solar system that has a mass double the mass of earth and density equal to the average density of the earth. If the weight of an object on earth is W, the weight of the same object on that planet will be:
HARD
A spiral galaxy can be approximated as an infinitesimally thin disc of a uniform surface mass density (mass per unit area) located at z=0, Two stars A and B start from rest from heights 2z0 and z0 (z0<< radial extent of the disc), respectively and fall towards the disc, cross over to the other side and execute periodic oscillations. The ratio of time periods of A and B is
EASY
A body of mass 60 g experiences a gravitational force of 3.0 N, when placed at a particular point. The magnitude of the gravitational field intensity at that point is
EASY
The value of acceleration due to gravity at Earth's surface is  9.8 m s-2 . The altitude above its surface at which the acceleration due to gravity decreases to  4.9 m s-2, is close to: (Radius of earth  =6.4×106 m )
EASY
A solid sphere of mass M and radius a is surrounded by a uniform concentric spherical shell of thickness 2a and mass 2M. The gravitational field at distance 3a from the centre will be:
MEDIUM
Infinite number of masses each of 3 kg are placed along a straight line at the distances of 1 m, 2 m,4 m,8 m, from a point 0 on the same line. If G is the universal gravitational constant, then the magnitude of gravitational field intensity at 0 is
EASY
Two planets A and B have the same average density. Their radii RA and RB are such that RA :RB=3:1. If gA and gB are the acceleration due to gravity at the surfaces of the planets, the gA :gB equals
MEDIUM

A body weighs 900 gm. wt on the surface of the earth. Its weight on the surface of a planet whose mass is 18th of that of the earth and radius is half that of the earth, is

EASY
Imagine a new planet having the same density as that of the earth but it is 3 times bigger than the earth in size. If the acceleration due to gravity on the surface of the earth is g and on the surface of the new planet is g', then
MEDIUM
The elongation of a wire on the surface of the earth is 10-4 m. The same wire of same dimensions is elongated by 6×10-5 m on another planet. The acceleration due to gravity on the planet will be _____ m s-2. (Take acceleration due to gravity on the surface of earth =10 m s-2)
EASY

A planet has double the mass of the earth. Its average density is equal to that of the earth. An object weighing W on earth will weigh on that planet:

EASY
If the radius of earth shrinks by 2% while its mass remains same. The acceleration due to gravity on the earth's surface will approximately
EASY
The value of acceleration due to gravity at a height of 10 km from the surface of earth is x. At what depth inside the earth is the value of the acceleration due to gravity has the same value x?
HARD
The mass density of a spherical body is given by ρr=kr for rR and ρr=0 for r>R, where r is the distance from the center. The correct graph that describes qualitatively the acceleration, a of a test particle as a function of r is:
MEDIUM
A ball is launched from the top of Mount Everest which is at an elevation of 9000 m. The ball moves in a circular orbit around the earth. The acceleration due to gravity near the earth's surface is g. The magnitude of the ball's acceleration while in orbit is,