Recent questions in Gravitation

If the distance between Earth and the sun were half its present value, the number of days in a year would be

asked Aug 22, 2013 by meena.p

1 answer

The mean radius of earth is R, its angular velocity on its own axis is 'w' and acceleration due to gravity is g. What will be the radius of orbit of a geostationary satellite ?

asked Aug 22, 2013 by meena.p

1 answer

A satellite revolving in a circular equatorial orbit of radius $r= 2 \times 10 ^4 km$ from west to East appears over a certain point at the equator every $11.6$ hours. Calculate the actual angular velocity of the satellite

asked Aug 22, 2013 by meena.p

1 answer

A geo stationary satellite orbits around the earth in a circular orbit of radius $36000km$. Then the time period of a spy satellite orbiting a few Kilometers above the earth's surface $(R_{earth}=6400 Km)$ will be approximately

asked Aug 22, 2013 by meena.p

1 answer

A satellite of mass $m_s$ revolving in a circular orbit of radius $r_s$ round the earth of mass M has a total energy E. Then its angular momentum will be

asked Aug 22, 2013 by meena.p

1 answer

A satellite is seen after each 8 hours over equator at a place on earth when its sence of rotation is opposite to the earth. The time interval after which it can be seen at the same place when sense of rotation of earth and satellite is same , will be

asked Aug 22, 2013 by meena.p

1 answer

A satellite can be in a geostationary orbit around the earth at a distance r from the center. If the angular velocity of earth about its axis doubles, a satellite can now be in a geostationary orbit around earth if its distance from the center is

asked Aug 22, 2013 by meena.p

1 answer

The height to which the acceleration due to gravity becomes $\large\frac{g}{9}$ (where g= acceleration due to gravity at surface of earth ) in terms of $R$, is

asked Aug 21, 2013 by meena.p

1 answer

Three identical stars each of mass M form an equilateral triangle that rotates around the center of the triangle. The system is isolated and edge length of the triangle of the triangle is L. The amount of work that is required to dismantle the system is

asked Aug 21, 2013 by meena.p

1 answer

An object of mass m starts falling towards planet of mass M and Radius R. As it reaches near the surface it passes through a small hole in the planet. The planet is made of two pieces, a sperical shell of negligible thickness and mass $\large\frac{2M}{3}$ and a point mass of $\large\frac{M}{3}$ at center. Change in the force of gravity experienced by the object is

asked Aug 21, 2013 by meena.p

1 answer

A geostationary satellite is at a height h above the surface of the earth If R is radius of earth 1) The mimimum coaltitude on earth upto which the satellite can be used for communication is $\sin ^{-1} \bigg(\large\frac{R}{R+a}\bigg)$ 2) The maximum coaltitude on earth upto which the satellite can be used for communication is $\sin ^{-1} \bigg(\large\frac{R}{R+h}\bigg)$ 3) Area of earth escaped from this satellite is given by $ (2 \pi R^2(1+\sin \theta)$ 4) Area of earth escaped from this satellite is given by $ (2 \pi R^2(1+\cos \theta)$

asked Aug 21, 2013 by meena.p

1 answer

Four similar particles of mass M are orbiting in a circle of radius r in the same angular direction because of their mutual gravitational attraction, velocity of particle is

asked Aug 21, 2013 by meena.p

1 answer

Infinite numbers of masses, each of mass m,are placed along straight line at distances of r,2r,4r,8r etc from a reference point O.Find the gravitational field at point O

asked Aug 21, 2013 by meena.p

1 answer

Three uniform spheres of mass M and radius R each are kept in such a way that each touches the other two. The magnitude of the gravitational force on any of the sphere due to the other two sphere is

asked Aug 21, 2013 by meena.p

1 answer

A satellite of mass m moves along an elliptical path around the earth. The areal velocity of satellite is proportional to

asked Aug 21, 2013 by meena.p

1 answer

A light planet revolving around a very massive star in a circular orbit of radius R with a period of revolution T. If the gravitational force of attraction between the planet and star is proportional to $R^{\large\frac{-5}{2}}$ then $T^2$ is proportional to

asked Aug 21, 2013 by meena.p

1 answer

A ring has a total mass M but not uniformly distributed over its circumference . The radius of ring is R. A Point mass m is placed at the center of the ring. Work done in taking away this point mass from center to infinity is

asked Aug 21, 2013 by meena.p

1 answer

A spaceship is lanunched into a circular orbit close to the earth's surface. What additional velocity has now to be imparted to the space ship in the orbit to overcome the gravitational pull. (Radius of earth$= 6400 km,g=9.8 m/s^2$)

asked Aug 20, 2013 by meena.p

1 answer

Three masses 1 kg 2 kg and 3 kg are placed at the vertices of an equilateral triangle of side 1m. Find the gravitational potential energy of the system $(G=6.67 \times 10^{-11} Nm^2 /kg^2)$

asked Aug 20, 2013 by meena.p

1 answer

A particle is projected from the surface of earth with an initial speed of 4 km/s . Find the maximum height attained by the particle.Radius of earth =6400 km and $g= 9.8 m/s^2$

asked Aug 20, 2013 by meena.p

1 answer

In a double star, two stars of masses $m_1$ and $m_2$ distant r apart revolve about their common center of mass under their mutual gravitational attraction. Find the ratio of their kinetic energies $K_1 :K_2$

asked Aug 20, 2013 by meena.p

0 answers

A Spherical hole of radius $\large\frac{R}{2}$ is made in a solid sphere of radius R. The mass of the sphere before hollowing was M. The gravitational field at the center of the hole due to the remaining mass is

asked Aug 20, 2013 by meena.p

1 answer

By what percent the energy of satallite has to be increased to shift it from an orbit of radius r to $\large\frac{3}{2}$$r$

asked Aug 20, 2013 by meena.p

1 answer

The ratio of kinetic energy required to raise a satellite upto a height 'h' to the kinetic energy of the satellite at that height (R-radius of earth)

asked Aug 20, 2013 by meena.p

1 answer

A satellite revolving roung the earth with orbital speed $v_0$, If it stops suddenly, the speed with which it will strike the surface of the earth would be (-ve escape velocity of the particle on earth's surface)

asked Aug 20, 2013 by meena.p

1 answer

Two bodies of masses $m_1$ and $m_2$ are initially at rest placed infinite distance apart. They are then allowed to move towards each other under their mutual gravitational attraction. Their relative velocity when they are 'r' distance apart is

asked Aug 20, 2013 by meena.p

1 answer

A planet revolves around the sum in an elliptical orbit of eccentricity e.If T is the time period of the planet, then the time spent by the planet between the ends of the planet between the ends of the minor axis close to the sun is

asked Aug 20, 2013 by meena.p

1 answer

What is the radius of moon's orbit around earth assuming the orbit to be circular ($g=9.8 m/s^2$; Radius of earth =6400 km; period of rotation of moon around the earth $=27.3\; days$

asked Aug 20, 2013 by meena.p

1 answer

At what velocity in (km/s) should a body be projected horizontally at a height of 30 km from the ground so that it becomes the satellite of the earth? neglect air friction. (radius of earth is $6370 \;Km$)

asked Aug 12, 2013 by meena.p

1 answer

An object lying at the equator will fly off the surface of the earth , if the speed of rotation of earth increases n time its present value, then n is

asked Aug 12, 2013 by meena.p

1 answer

The eacape velocity from earth is 11km/s. The escape velocity from a planet having twice the radius and same mean density as that of earth is

asked Aug 12, 2013 by meena.p

1 answer

A Spherical uniform planet is rotating about its axis . The velocity of a point on its equator is v. Due to the rotation of planet about its axis the acceleration due to gravity of at equator is $\large\frac{1}{2}$ of acceleration due to gravity at poles. The escape velocity of a particle on the poles of planet in terms of v

asked Aug 12, 2013 by meena.p

1 answer

Suppose the gravitational force varies inversely as the $n^{th}$ power of distance, then the time period of planet in circular orbit of Radius 'R' around the sun will be proportional to

asked Aug 11, 2013 by meena.p

1 answer

Average density of the earth

asked Aug 11, 2013 by meena.p

1 answer

A particle of mass 10 g is kept on surface of a uniform sphere of mass 100 kg and radius 10 cm. Find the work done against gravitational force between them, to take the particle for away from sphere $(G=6.67 \times 10^{-11} Nm^2/kg)$

asked Aug 10, 2013 by meena.p

1 answer

Light planet is revolving around a very massive star in a circular orbit of radius 'r' with a period of revolution T. On what power of 't' will the square of period depend if the gravitational force of attraction between planet and the star is proportional to $r^{\large\frac{-5}{2}}$

asked Aug 10, 2013 by meena.p

1 answer

If the sun is about $9.3\times10^7\; km $ away from the earth, and its mass is $3.24\times10^5 \times m_e$, where $m_e$ is the mass of the earth, how far from the earth must a body be along a line towards the sun so that the sun’s gravitational pull balances the earth's?

asked Aug 10, 2013 by meena.p

1 answer

Planet Neptune travels around the sun with a period of 165 years. Find the ratio of $\large\frac{R_2}{R_1}$ where $R_2$ radius of Neptune orbit and $R_1$ radius of earth , both being considerd circular.

asked Aug 10, 2013 by meena.p

1 answer

A rocket is launched with velocity 10 km/s if radius of earth is R, then maximum height attained by it will be

asked Aug 10, 2013 by meena.p

1 answer

If radius of the earth were to shrink by one percent, its mass remaining same the value of g on the earth's surface would

asked Aug 10, 2013 by meena.p

1 answer

A simple pendulum has a time period $T_1$ When on earth's surface, and $T_2$ When taken to a height R above the earth's surface, where R is radius of earth. Then $\large\frac{T_2}{T_1}$ is

asked Aug 10, 2013 by meena.p

1 answer

Two satellites have their masses in the ratio $3:1$ The ratio of the orbit (circular ) are $1:4$ then the ratio of total mechanical energy of A and B

asked Aug 10, 2013 by meena.p

1 answer

For a planet moving aroung the sun in an elliptical orbit, which of the following quantities remain constant?

asked Aug 9, 2013 by meena.p

1 answer

Two planets have same average density but their radii are $R_1$ and $R_2$. If acceleration due to gravity on these planets are $g_1$ and $g_2$ respectively.

asked Aug 9, 2013 by meena.p

1 answer

A planet moves around the sun. At a given point P,it is closet from the sun at a distance $d_1$ and speed $v_1$ At another point Q when it is farthest from the sun at a distance $d_2$, its speed will be

asked Aug 9, 2013 by meena.p

1 answer

A satellite moves in a circle around earth The radius of this circle is equal to one half of the radius of the moon's orbet. The satellite completes one revolution in

asked Aug 9, 2013 by meena.p

1 answer

The value of escape velocity on a certain planet is $ 2 km/s$ then the value of arbital speed for a satellite arbiting close to its surface is

asked Aug 9, 2013 by meena.p

1 answer

Gas escapes from the surface of a planet because it aquires escape velocity. The escape velocity will depend on which of the following <br> 1) Mass of planet <br> 2) Mass of particle escaping <br> 3) Temperature of the planet <br> 4) Radius of the planet

asked Aug 9, 2013 by meena.p

1 answer

In the gravitational field , at a point where the gravitational potential is zero

asked Aug 9, 2013 by meena.p

1 answer

The density of a newly discovered planet is twice that of earth . The acceleration due to gravity at the surface of the planet is equal to that at the surface of earth. If the radius of earth is R, radius of planet will be

asked Aug 9, 2013 by meena.p

1 answer

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