## Gravitation Questions and Answers Part-19

1. Two satellites of masses $m_{1}$ and $m_{2}\left(m_{1}>m_{2}\right)$    are revolving round the earth in circular orbits of radius $r_{1}$ and $r_{2}\left(r_{1}>r_{2}\right)$    respectively. Which of the following statements is true regarding their speeds $v_{1}$ and $v_{2}$ ?
a) $v_{1}=v_{2}$
b) $v_{1}< v_{2}$
c) $v_{1}>v_{2}$
d) $\frac{v_{1}}{r_{1}}=\frac{v_{2}}{r_{2}}$

Explanation:

2. A satellite which is geostationary in a particular orbit is taken to another orbit. Its distance from the centre of earth in new orbit is 2 times that of the earlier orbit. The time period in the second orbit is
a) 4.8 hours
b) $48\sqrt{2}$   hours
c) 24 hours
d) $24\sqrt{2}$   hours

Explanation:

3.The ratio of the K.E. required to be given to the satellite to escape earth's gravitational field to the K.E. required to be given so that the satellite moves in a circular orbit just above earth atmosphere is
a) One
b) Two
c) Half
d) Infinity

Explanation:

4.An astronaut orbiting the earth in a circular orbit 120 km above the surface of earth, gently drops a spoon out of space-ship. The spoon will
a) Fall vertically down to the earth
b) Move towards the moon
c) Will move along with space-ship
d) Will move in an irregular way then fall down to earth

Explanation: The velocity of the spoon will be equal to the orbital velocity when dropped out of the space-ship

5. The period of a satellite in a circular orbit around a planet is independent of
a) The mass of the planet
b) The radius of the planet
c) The mass of the satellite
d) All the three parameters (a), (b) and (c)

Explanation: The mass of the satellite

6. The relay satellite transmits the T.V. programme continuously from one part of the world to another because its
a) Period is greater than the period of rotation of the earth
b) Period is less than the period of rotation of the earth about its axis
c) Period has no relation with the period of the earth about its axis
d) Period is equal to the period of rotation of the earth about its axis

Explanation: Telecommunication satellites are geostationary satellite

7. Two satellites A and B go round a planet P in circular orbits having radii 4R and R respectively. If the speed of the satellite A is 3V, the speed of the satellite B will be
a) 12 V
b) 6 V
c) $\frac{4}{3}v$
d) $\frac{3}{2}v$

Explanation:

8. A geostationary satellite
a) Revolves about the polar axis
b) Has a time period less than that of the near earth satellite
c) Moves faster than a near earth satellite
d) Is stationary in the space

Explanation: A geostationary satellite revolves about the polar axis

9. A small satellite is revolving near earth's surface. Its orbital velocity will be nearly
a) 8 km/sec
b) 11.2 km/sec
c) 4 km/sec
d) 6 km/sec