# Topic: UNIT VI: Gravitation (Test 1)

Topic: UNIT VI: Gravitation
Q.1
The linear momentum and position vector of the planet is perpendicular to each other at
A. perihelion and aphelion
B. at all points
C. only at perihelion
D. no point
Explaination / Solution:
No Explaination.

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Q.2
If the masses of the Earth and Sun suddenly double, the gravitational force between them will
A. remain the same
B. increase 2 times
C. increase 4 times
D. decrease 2 times
Explaination / Solution:
No Explaination.

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Q.3
A planet moving along an elliptical orbit is closest to the Sun at distance r1 and farthest away at a distance of r2. If v1 and v2 are linear speeds at these points respectively. Then the ratio V1/V2 is
A. B. C. D. Explaination / Solution:
No Explaination.

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Q.4
The time period of a satellite orbiting Earth in a cirular orbit is independent of
B. The mass of the satellite
C. Both the mass and radius of the orbit
D. Neither the mass nor the radius of its orbit
Explaination / Solution:
No Explaination.

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Q.5
If the distance between the Earth and Sun were to be doubled from its present value, the number of days in a year would be
A. 64.5
B. 1032
C. 182.5
D. 730
Explaination / Solution:
No Explaination.

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Q.6
According to Kepler’s second law, the radial vector to a planet from the Sun sweeps out equal areas in equal intervals of time. This law is a consequence of
A. conservation of linear momentum
B. conservation of angular momentum
C. conservation of energy
D. conservation of kinetic energy
Explaination / Solution:
No Explaination.

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Q.7
The gravitational potential energy of the Moon with respect to Earth is
A. always positive
B. always negative
C. can be positive or negative
D. always zero
Explaination / Solution:
No Explaination.

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Q.8
The kinetic energies of a planet in an elliptical orbit about the Sun, at positions A, B and C are KA, KB and KC respectively. AC is the major axis and SB is perpendicular to AC at the position of the Sun S as shown in the figure. Then
A. KA > KB >KC
B. KB < KA <KC
C. KA < KB <KC
D. KB > KA >KC
Explaination / Solution:
No Explaination.

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Q.9
The work done by the Sun’s gravitational force on the Earth is
A. always zero
B. always positive
C. can be positive or negative
D. always negative
Explaination / Solution:
No Explaination.

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Q.10
If the mass and radius of the Earth are both doubled, then the acceleration due to gravity g'
A. remains same
B. g/2
C. 2g
D. 4g