Two satellites A and B go around the earth in a circular orbits at a height of RA and RB respectively from the surface of the earth. Assume the earth to be a uniform sphere of radius RE. The ratio of magnitudes of the velocities of the statellites VA/VB =
√RB/RA
RB + RE/(RA +RE)
√(RB + RE)/(RA + RE)
√RA /RB
A gun is aimed at a target in line with its barrel. The target is released and allowed to fall under gravity, at the instant, the gun is fired. The bullet will :
pass above the target
pass below the target
hit the target
certainly hit the target
Degenerate electron pressure will not be sufficient to prevent core collapse of 'white dwarf' if its mass becomes n times of solar mass. Value of n is:
0.5
0.8
1
1.4
A body is projected vertically upwards from the surface of the earth with a velocity equal to half the escape velocity. If R is the radius of the earth, maximum height attained by the body from the surface of the earth is
R/6
R/3
2R/3
R
The mass of a planet is half that of the earth and the radius of the planet is one-fourth that of earth. If we plan to send an artificial satellite from the planet, the escape velocity will be, (escape velocity on earth ve =11 km- s-1)
11 km-s-1
5.5 km-s-1
15.5 km-s-1
7.78 km-s-1
The coefficient of kinetic friction between a body and the surface of an inclined plane at 450 is 0.5. If g = 9.8 ms-2,the acceleration of the body down the inclined plane, in ms-2is:
4.9/√2
4.9
4.9√2
19.6√2
If the earth suddenly stops rotating, the value of g at equator would :
decrease
remain unchanged
increase
become zero