### NEET Physics - New - Gravitation

#### Question - 1

The kinetic energies of a planet in an elliptical orbit about the Sun, at positions A, B and Care KA, KBand 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 KB > KA > KC
• B KA> KB > KC
• C KA< KB < KC
• D KB < KA < KC

#### Question - 2

If the mass of the Sun were ten times smaller and the universal gravitational constant were ten times larger in magnitude, which of the following is not correct?

• A Time period of a simple pendulum on the Earth would decrease
• B Walking on the ground would become more difficult
• C Raindrops will fall faster
• D 'g' on the Earth will not change

#### Question - 3

The acceleration due to gravity at a height 1 km above the Earth is the same as at a depth d below the surface of Earth. Then

• A d = 2km
• B d = 1/2km
• C d = 1km
• D d = 3/2km

#### Question - 4

Starting from the centre of the Earth having radius R, the variation of g (acceleration due to gravity) is shown by

• A
• B
• C
• D

#### Question - 5

A satellite of mass m is orbiting the earth (of radius R) at a height h from its surface. The total energy of the satellite in terms of got the value of acceleration due to gravity at the earth's surface, is

• A mgoR2/2(R+h)
• B -mgoR2/2(R+h)
• C 2mgoR2/(R +h)
• D -2 mgoR2/(R +h)

#### Question - 6

A remote sensing satellite of Earth revolves in a circular orbit at a height of 0.25x106 m above the surface of Earth. If Earth's radius is 6.38x 106 and g=9.8 m/s2, then the orbital speed of the satellite is:

• A 7.76km/s
• B 8.5km/s
• C 9.13km/s
• D 6.67km/s

#### Question - 7

A satellite S is moving in an elliptical orbit aroundthe Earth. The mass of the satellite is very small as compared to the mass of the Earth. Then,

• A the angular momentum of S about the centre of the Earth changes in direction, but its magnitude remains constant
• B the total mechanical energy of S varies periodically with time
• C the linear momentum of S remains constant in magnitude
• D the acceleration of S is always directed towards the centre of the Earth

#### Question - 8

Kepler's third law states that square of period of revolution (T) of a planet around the Sun, is proportional to third power of average distance r between the Sun and planet, i.e., T2=Kr3, here K is constant. If the masses of the Sun and planet are M and m respectively, then as per Newton's law of gravitation force of attraction between them is F=GMm/r2, here G is gravitational constant. The relation between G and K is described as

• A GK=4π2
• B GMK=4π2
• C K=G
• D K=l/G

#### Question - 9

A black hole is an object whose gravitational field is so strong that even light cannot escape from it. To what approximate radius would earth (mass = 5.98 x 1024 kg) have to be compressed to be a black hole?

• A 10-9 m
• B 10-6 m
• C 10-2 m
• D 100 m

#### Question - 10

The height at which the weight of a body becomes $1 \over16$th, its weight on the surface of Earth (radius R), is:

• A 5R
• B 15R
• C 3R
• D 4R