Recent questions in Physics

The radius of planet is R. A satellite revolves around it in a circular orbit of radius r with angular speed 'w'. The acceleration due to gravity on the planet's surface will be

asked Aug 29, 2013 by meena.p

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A planet is moving in an elliptical path around the sun of shown speed of planet in position P and Q are $v_1$ and $v_2$ respectively with $SP= r_1\;and SQ=r_2$ then $v_1/v_2$ is equal to

asked Aug 29, 2013 by meena.p

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The magnitude of potential energy per unit mass of object at surface of earth is E. then the escape velocity of the object is

asked Aug 29, 2013 by meena.p

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Speed of a planet in an elliptical orbit with semi major axis 'a' about sum of mass M at a distance r from the sun is

asked Aug 29, 2013 by meena.p

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A smooth tunnel is dug along the radius of earth that ends at center. A ball is released from the surface of earth along tunnel. What is the velocity when it strike the center?

asked Aug 29, 2013 by meena.p

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The density of case of a planet is $s_1$ and that of the outer shell is $s_2$.The radius of case and that of the planet are R and 2R respectively. Gravitational acceleration at the surface of the planet is same as at a depth R. Find $\large\frac{s_1}{s_2}$

asked Aug 29, 2013 by meena.p

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A uniform rod of length $'l'$ whose mass per unit length is $\lambda$. The gravitational force on a particle of mass m located at a distance d from one end of the rod as shown is

asked Aug 29, 2013 by meena.p

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Two satellites are moving in a common plane along circular paths. with one having angular velocity $w_1=1.09 \times 10^{-3} rad/s$ and another $w_2=1.08 \times 10^{-3}rad /s$. Find time interval which seperates the periodic approaches of the satellites to each other over minimum distance, if they are revolving in opposite sense.

asked Aug 26, 2013 by meena.p

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If a planet orbiting the sun in a circular orbit suddenly stops, it will fall onto the sun in a time n(T) where T is the period of planets revolution , then n is

asked Aug 26, 2013 by meena.p

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An artificial satellite of mass m moves in an orbit whose radius is n times the radius of earth. Assuming the resistance to the motion is proportional to square of velocity ie $F= av^2$ where a is a constant. How long will the satellite take to fall to earth. M-mass of earth R- radius of earth

asked Aug 26, 2013 by meena.p

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A body of mass m ascends from the earth's surface with zero initial velocity due to action of two forces as shown. The force $F$ varying with $h$ as $\hat F=-2m \vec {g} (1-ah)$ where a is constant. Find the maximum height atained by the body t

asked Aug 26, 2013 by meena.p

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If a body is to be projected vertically upwards from the surface of the earth to reach a height nR then the velocity with which it is to be projected is

asked Aug 26, 2013 by meena.p

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Mass density of a solid sphere is $\rho$. Radius of sphere is R. The gravitational field at a distance $r$ from the center of the sphere inside it is

asked Aug 26, 2013 by meena.p

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If the period of revolution of an artificial satellite just above the earth's surface is T and density of earth is $\rho$ then $\rho T ^2$

asked Aug 26, 2013 by meena.p

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The work done in slowly lifting a body from earth's surface to a height R (radius of earth) is equal to two times the work done in lifing the same body from earth's surface to height h there h is equal to

asked Aug 26, 2013 by meena.p

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A uniform ring of mass $M$ and radius $R$ is placed directly above a uniform sphere of mass $8M$ and of radius $R$. The center of the ring is at a distance of $d= \sqrt 3 R$ from the center of the sphere. The gravitational attraction between the sphere and ring is

asked Aug 26, 2013 by meena.p

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A particle of mass M is placed at the center of a uniform sperical shell of mass 2M and radius R. The gravitational potential on the surface of the shell is

asked Aug 26, 2013 by meena.p

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Three particles each having a mass 100 gm are placed on the verticles of an equilateral triangle of side 20 cm. The work done in increasing the side of their triangle to 40 cm is $(G= 6.67 \times 10^{-11}\;Nm^2/kg^2)$

asked Aug 26, 2013 by meena.p

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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

asked Aug 24, 2013 by meena.p

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Suppose the gravitational force varies inversely as the n-th power of distance. Then the time period of a planet in circular orbit of radius 'r' around the sun will be proportional to

asked Aug 24, 2013 by meena.p

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Mean distance of mars from sun is 1.524 times the distance of earth from sun. The period of revolution of mars around the sun is

asked Aug 24, 2013 by meena.p

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If a graph is plotted between $T^2$ and $r^3$ for a planet the slope will be

asked Aug 24, 2013 by meena.p

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A particle is suspended from a spring and it stretches the spring by 1 cm on the surface of the earth. The same particle will stretch the same spring at a place 800 Km above the earth by

asked Aug 24, 2013 by meena.p

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The radius of the earth $R_e$ and the acceleration due to gravity at its surface is g. The work required to rising a body of mass m to height h from the surface of the earth will be

asked Aug 23, 2013 by meena.p

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Three particles of equal mass m are situated at verticles of a equilateral triangle of side l. What should be velocity of each particle so that they move on a circular path without changing l

asked Aug 23, 2013 by meena.p

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What would be the angular speed of earth, so that bodies lying on equator may appear weightless? $(g=10 m/s^2\; R=6400km)$

asked Aug 23, 2013 by meena.p

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Two bodies of mass $10^2 kg$ and $10^3kg$ are lying 1m apart. The gravitational potential at mid point of line joining them is

asked Aug 23, 2013 by meena.p

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A mass M is split into two parts m and (M-m) which are then separated by a certain distance. What ratio of m/M maximise the gravitational force between the parts?

asked Aug 23, 2013 by meena.p

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A geostationary satellite is orbiting the earth at a height of 6R where R is radius of earth. The time period of another satellite at a height of $2.5 R$ from the surface of earth is

asked Aug 23, 2013 by meena.p

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The ratio of radius of two planets is K and ratio of acceleration due to gravity of both planet is G. What will be the ratio of their escape velocity ?

asked Aug 23, 2013 by meena.p

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The mass of earth is $6.00 \times 10^{24} \;kg $ and that of the moon is $7.40 \times 10 ^{22} \;kg \;$ and $G= 6.67 \times 10^{-11} Nm^2 /kg^2$. potential energy of the system is $-7.79 \times 10^{28} J$. The mean distance of between earth and moon is

asked Aug 23, 2013 by meena.p

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The gravitational field due to mass distribution is $ E= k/x^3$ in the x direction where k is a constant. Taking gravitational potential to be zero at infinity, its value at a distance x is

asked Aug 23, 2013 by meena.p

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What is the acceleration due to gravity at surface of mass if its diameter is $6760\;km$ and mass is one tenth that of earth. The diameter of earth is $12742\;km$ acceleration due to gravity on earth $=9.8 m/s^2$

asked Aug 23, 2013 by meena.p

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A stone is dropped freely into a tunnel along the diameter of the earth. When it reaches the center of earth then it has only

asked Aug 23, 2013 by meena.p

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At what height from the ground will the value of 'g' be the same as that in 10 km deep mine below the surface of earth

asked Aug 23, 2013 by meena.p

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A planet moves in an elliptical orbit with sun at one of its focii <br> 1) In path QRP work done by gravity is positive . <br> 2) In path PSQ work done by gravity is negative . <br> 3) Linear velocity of rotation from Q to P via R decreases. <br> 4) Gravitational potential energy increases in going from P to Q via R

asked Aug 22, 2013 by meena.p

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The Planet mercury is revolving in an elliptical orbit around the sun as shown. Kinetic energy will be greatest at

asked Aug 22, 2013 by meena.p

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As measured by an observer on earth, what would be the difference, if any, in the period of two satellite each in a circular orbit near the earth's equatorial plane, but one moving eastward and other moving westward.

asked Aug 22, 2013 by meena.p

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A satellite of mass m is orbiting the earth at a height 'h' from its surface. If M is Mass of the earth and R its radius then how much energy must be spent to pull the satellite out of the earth's gravitational field?

asked Aug 22, 2013 by meena.p

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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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

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