EASY
JEE Main/Advance
IMPORTANT
Earn 100

The minimum and maximum distances of a satellite from the centre of the Earth are 2R  and 4R  respectively, where, R  is the radius of Earth and M is the mass of the Earth. Radius of curvature at the point of minimum distance isαR3 , then the value of α is,

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Important Questions on Gravitation

EASY
JEE Main/Advance
IMPORTANT
A satellite of mass m  is in an elliptical orbit around Earth of mass M(Mm) . The speed of the satellite at its nearest point to the Earth is 6GM5R, where R=perigee(closest distance to the Earth). It is desired to transfer this satellite into a circular orbit around the Earth of radius equal its largest distance from the Earth. If the increase in its speed to be imparted at the apogee (farthest point on the elliptical orbit) is of the form GMRa3-b15. Find a+b.
EASY
JEE Main/Advance
IMPORTANT
A body is launched from the Earth's surface at an angle α=30° to the horizontal with speed v0=1.5GMR. Neglecting air resistance and Earth's rotation, if the height to which the body will rise is 72+βR, then find value of β.
EASY
JEE Main/Advance
IMPORTANT
Distance between the centres of two starts is 10a . The masses of these stars are M  and 16M  and their radius a and 2a respectively. A body of mass m  is fired straight from the surface of the larger star towards the surface of the smaller star. Now if its minimum initial speed to reach the surface of the smaller star in terms of G, M and a is 32βGMa, then find value of β.
EASY
JEE Main/Advance
IMPORTANT
If the potential energy of a system of four particles placed at the vertices of a square of side l is -5.41Gmαl and the potential at the centre of the square is -4βGml, then find α+β.
HARD
JEE Main/Advance
IMPORTANT
A satellite of mass Ms is orbiting the Earth in a circular orbit of radius Rs. It starts losing energy slowly at a constant rate C due to friction. If Me and Re denote the mass and radius of the Earth respectively, show that the satellite falls on the Earth in a limit time t given by t=GMsMe2C1Re-1Rs
HARD
JEE Main/Advance
IMPORTANT
A rocket starts vertically upwards with speed v0. If its speed v at a height h is given by v02-v2=(βgh)1+hR, then find value of β. 
MEDIUM
JEE Main/Advance
IMPORTANT
A cord of length 64 m is used to connect a 100 kg  astronaut to spaceship whose mass is much larger than that of the astronaut. If the value of the tension in the cord is x×10-2 N, then find value of x. Assume that the spaceship is orbiting near Earth surface also assume that the spaceship and the astronaut fall on a straight line from the Earth centre. The radius of the Earth is 6400 km .
HARD
JEE Main/Advance
IMPORTANT
A remote sensing satellite is revolving in an orbit of radius x on the equator of Earth. If the area on Earth surface in which satellite can not send message is β-x2-R2x4πR2, then find β.