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

(A)

F/3

(B)

F/9

(C)

3F

(D)

F

Question-2

What will be the formula of the mass in terms of g, R and G? (R = radius of earth)

(A)

g^{2}^{R}/G

(B)

G R^{2}/g

(C)

G^{ R}/g

(D)

g R^{2}/G

Question-3

A ball is dropped from a satellite revolving around the earth at a height of 120km.The ball will

(A)

Continue to move with same speed along a straight line tangentially to the satellite at that time

(B)

Continue to move with the same speed along the original orbit of satellite

(C)

Fall down to earth gradually

(D)

Go far away in space

Question-4

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

(A)

^{mgh}/R

(B)

^{2}/3 mgR

(C)

^{3}/4 mgR

(D)

^{mgR}/2

Question-5

A planet is moving in an elliptical orbit around the sun. If T, U, E and L stands 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?

(A)

T is conserved

(B)

U is always positive

(C)

E is always negative

(D)

L is conserved but direction of vector L changes continuously

Question-6

The largest and the shortest distance of the earth from the sun are r_{1} and r_{2}. Its distance from the sun when it is perpendicular to the major axis of the orbit drawn from the sun is

(A)

(B)

(C)

(D)

Question-7

If the gravitational force between two objects were proportional to ^{1}/R (and not as^{ 1}/R^{2}), where R is separation between them, then a particle in circular orbit under such a force would have its orbital speed v proportional to

(A)

^{1}/R^{2}

(B)

R^{0}

(C)

R

(D)

^{1}/R

Question-8

A satellite A of mass m is at a distance r from the surface of the earth. Another satellite B of mass 2 m is at a distance of 2 r from the earth's surface. Their time periods are in the ratio of

(A)

1 : 2

(B)

1 : 6

(C)

1 : 16

(D)

1 : 2√2

Question-9

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?

(A)

5

(B)

4

(C)

3

(D)

2

Question-10

The acceleration due to gravity on the planet A is 9 times the acceleration due to gravity on planet B. A man jumps to a height of 2m on the surface of A. What is the height of jump by the same person on the planet B?

(A)

6 m

(B)

^{2}/3 m

(C)

^{2}/9 m

(D)

18 m

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