A body of mass m is placed on earth's surface. It is then taken from earth's surface to a height h = 3R, then the change in gravitational potential energy is
mgh/R
2/3 mgR
3/4 mgR
mgR/2
A second pendulum is mounted in a rocket. Its period of oscillation decreases when the rocket
Comes down with uniform acceleration
Moves round the earth in a geostationary orbit
Moves up with a uniform velocity
Moves up with uniform acceleration
A satellite A of mass m is at a distance r from the surface of the earth. Another satellite B of mass 2m is at a distance of 2r from the earth's surface. Their time periods are in the ratio of
1 : 2
1 : 16
1 : 32
1 : 2√2
The distance of two planets from the sun are 1013 and 1012 m respectively. The ratio of time periods of these two planets is
100
10√10
√10
The escape velocity from earth is 11.2 km/s. If a body is to be projected in a direction making an angle 45o to the vertical, then the escape velocity is
11.2 × 2 km/s
11.2 km/s
11.2/√2 km/s
11.2√2 km/s
A body attains a height equal to the radius of the earth. The velocity of the body with which it was projected is
Two spheres of masses m and M are situated in air and the gravitational force between them is F. The space around the masses is now filled with a liquid of specific gravity 3. The gravitational force will now be
F/3
F/9
3F
F
The period of revolution of planet A around the sun is 8 times that of B. The distance of A from the sun is how many times greater than that of B from the sun?
5
4
3
2
The largest and the shortest distance of the earth from the sun are r1 and r2. Its distance from the sun when it is perpendicular to the major axis of the orbit drawn from the sun is
A planet is moving in an elliptical orbit around the sun.If T, U, E and L stand for its kinetic energy, gravitational potential energy, total energy and magnitude of angular momentum about the centre of force, which of the following is correct?
T is conserved
U is always positive
E is always negative
L is conserved but direction of vector L changes continuously
