Textbook Solutions: Space Missions | Science and Technology Class 10 (Maharashtra SSC Board) PDF Download

 Page 1


Space Missions 
Exercise 
Q. 1. Fill in the blanks and explain the statements with reasoning: 
 
a. If the height of the orbit of a satellite from the earth surface is increased, the 
tangential velocity of the satellite will … 
b. The initial velocity (during launching) of the Mangalyaan, must be greater than 
…………..of the earth. 
Answer : (a) If the height of the orbit of a satellite from the earth surface is increased, 
the tangential velocity of the satellite will decreases. 
 
Explanation: As tangential velocity of satellite is inversely proportional to the height of 
orbit of satellite from earth’s surface. 
V= v 
Where V = tangential velocity 
G = gravitational constant 
M = mass of earth 
R = radius of earth 
h = height of satellite above earth surface 
(b) The initial velocity (during launching) of the Mangalyaan, must be greater 
than escape velocity of the earth. 
Explanation: Space crafts should escape the earth’s gravitational force to travel to outer 
space. Escape velocity is the minimum speed required by an object i.e. satellite to 
escape from the gravitational force of the earth. The minimum velocity of satellite should 
be 11.2 km/sec. 
Q. 2. State with reasons whether the following sentences are true or false 
 
a. If a spacecraft has to be sent away from the influence of earth’s gravitational 
field, its velocity must be less than the escape velocity. 
b. The escape velocity on the moon is less than that on the earth. 
c. A satellite needs a specific velocity to revolve in a specific orbit. 
d. If the height of the orbit of a satellite increases, its velocity must also increase. 
Page 2


Space Missions 
Exercise 
Q. 1. Fill in the blanks and explain the statements with reasoning: 
 
a. If the height of the orbit of a satellite from the earth surface is increased, the 
tangential velocity of the satellite will … 
b. The initial velocity (during launching) of the Mangalyaan, must be greater than 
…………..of the earth. 
Answer : (a) If the height of the orbit of a satellite from the earth surface is increased, 
the tangential velocity of the satellite will decreases. 
 
Explanation: As tangential velocity of satellite is inversely proportional to the height of 
orbit of satellite from earth’s surface. 
V= v 
Where V = tangential velocity 
G = gravitational constant 
M = mass of earth 
R = radius of earth 
h = height of satellite above earth surface 
(b) The initial velocity (during launching) of the Mangalyaan, must be greater 
than escape velocity of the earth. 
Explanation: Space crafts should escape the earth’s gravitational force to travel to outer 
space. Escape velocity is the minimum speed required by an object i.e. satellite to 
escape from the gravitational force of the earth. The minimum velocity of satellite should 
be 11.2 km/sec. 
Q. 2. State with reasons whether the following sentences are true or false 
 
a. If a spacecraft has to be sent away from the influence of earth’s gravitational 
field, its velocity must be less than the escape velocity. 
b. The escape velocity on the moon is less than that on the earth. 
c. A satellite needs a specific velocity to revolve in a specific orbit. 
d. If the height of the orbit of a satellite increases, its velocity must also increase. 
Answer : (a) False 
 
Explanation: Space crafts should escape the earth’s gravitational force to travel to outer 
space. Escape velocity is the minimum speed required by an object i.e. satellite to 
escape from the gravitational force of the earth. So its speed should be more than the 
escape velocity. 
(b) True 
Explanation: The mass of moon is less than the mass of earth so its gravitational pull is 
less hence escape velocity on moon is less as compared to earth. 
(c) True 
Explanation: A satellite requires a specific velocity to revolve in a specific orbit called 
critical velocity which acts as a tangential direction to the orbit. 
(d) False 
Explanation: If the height of the orbit of a satellite increases, its velocity decreases. As 
tangential velocity of satellite is inversely proportional to the height of orbit of satellite 
from earth’s surface. 
V= v 
Where V = tangential velocity 
G = gravitational constant 
M = mass of earth 
R = radius of earth 
h = height of satellite above earth surface 
Q. 3. A. Answer the following question: 
 
What is meant by an artificial satellite? How are the satellites classified based on 
their functions? 
Answer : A manmade object revolves around the earth or any other planet in a fixed 
orbit is called an artificial satellite. 
Based on their function satellites are of various types- 
Page 3


Space Missions 
Exercise 
Q. 1. Fill in the blanks and explain the statements with reasoning: 
 
a. If the height of the orbit of a satellite from the earth surface is increased, the 
tangential velocity of the satellite will … 
b. The initial velocity (during launching) of the Mangalyaan, must be greater than 
…………..of the earth. 
Answer : (a) If the height of the orbit of a satellite from the earth surface is increased, 
the tangential velocity of the satellite will decreases. 
 
Explanation: As tangential velocity of satellite is inversely proportional to the height of 
orbit of satellite from earth’s surface. 
V= v 
Where V = tangential velocity 
G = gravitational constant 
M = mass of earth 
R = radius of earth 
h = height of satellite above earth surface 
(b) The initial velocity (during launching) of the Mangalyaan, must be greater 
than escape velocity of the earth. 
Explanation: Space crafts should escape the earth’s gravitational force to travel to outer 
space. Escape velocity is the minimum speed required by an object i.e. satellite to 
escape from the gravitational force of the earth. The minimum velocity of satellite should 
be 11.2 km/sec. 
Q. 2. State with reasons whether the following sentences are true or false 
 
a. If a spacecraft has to be sent away from the influence of earth’s gravitational 
field, its velocity must be less than the escape velocity. 
b. The escape velocity on the moon is less than that on the earth. 
c. A satellite needs a specific velocity to revolve in a specific orbit. 
d. If the height of the orbit of a satellite increases, its velocity must also increase. 
Answer : (a) False 
 
Explanation: Space crafts should escape the earth’s gravitational force to travel to outer 
space. Escape velocity is the minimum speed required by an object i.e. satellite to 
escape from the gravitational force of the earth. So its speed should be more than the 
escape velocity. 
(b) True 
Explanation: The mass of moon is less than the mass of earth so its gravitational pull is 
less hence escape velocity on moon is less as compared to earth. 
(c) True 
Explanation: A satellite requires a specific velocity to revolve in a specific orbit called 
critical velocity which acts as a tangential direction to the orbit. 
(d) False 
Explanation: If the height of the orbit of a satellite increases, its velocity decreases. As 
tangential velocity of satellite is inversely proportional to the height of orbit of satellite 
from earth’s surface. 
V= v 
Where V = tangential velocity 
G = gravitational constant 
M = mass of earth 
R = radius of earth 
h = height of satellite above earth surface 
Q. 3. A. Answer the following question: 
 
What is meant by an artificial satellite? How are the satellites classified based on 
their functions? 
Answer : A manmade object revolves around the earth or any other planet in a fixed 
orbit is called an artificial satellite. 
Based on their function satellites are of various types- 
a. Weather satellite- Study and prediction of weather. 
b. Communication satellite – Establish communication between different location of the 
world. 
c. Broadcast satellite – Telecasting of tv programmes. 
d. Navigational satellite – Fix the location of any place on the earth’s surface. 
e. Military satellite – Collect information for security aspects. 
f. Earth observation satellite – Study of forests, deserts, oceans, polar ice etc. 
Q. 3. B. Answer the following question: 
 
What is meant by the orbit of a satellite? On what basis and how are the orbits of 
artificial satellites classified? 
Answer : An orbit is a regular, repeating path that satellite takes around the earth to 
revolve. Depending on the height of the satellite’s orbit above the earth surface, the 
orbit of satellites are classified as follows- 
 
i. High earth orbits- If the height of the satellite’s orbit above the earth’s surface is 
greater than or equal to 35780 km, the orbit is called high earth orbit. These satellites 
almost take 24 hours to complete one revolution. These are also called geosynchronous 
satellites. They are used in meterology, carry signals for telephone, TV, radio etc. 
ii. Medium earth orbits- If height of the satellite orbit above the earth’s surface is in 
between 2000 km and 35780 km the orbits are called medium earth orbits. 
iii. Low earth orbits – If the height of the satellite orbit above the earth’s surface is in 
between 180 km and 2000 km the orbits are called low earth orbits. They are used for 
scientific experiments and atmospheric studies. 
Q. 3. C. Answer the following question: 
 
Why are geostationary satellites not useful for studies of polar regions? 
Answer : Geostationary satellites orbit is above the equator so they are not useful for 
studies of polar regions. 
Page 4


Space Missions 
Exercise 
Q. 1. Fill in the blanks and explain the statements with reasoning: 
 
a. If the height of the orbit of a satellite from the earth surface is increased, the 
tangential velocity of the satellite will … 
b. The initial velocity (during launching) of the Mangalyaan, must be greater than 
…………..of the earth. 
Answer : (a) If the height of the orbit of a satellite from the earth surface is increased, 
the tangential velocity of the satellite will decreases. 
 
Explanation: As tangential velocity of satellite is inversely proportional to the height of 
orbit of satellite from earth’s surface. 
V= v 
Where V = tangential velocity 
G = gravitational constant 
M = mass of earth 
R = radius of earth 
h = height of satellite above earth surface 
(b) The initial velocity (during launching) of the Mangalyaan, must be greater 
than escape velocity of the earth. 
Explanation: Space crafts should escape the earth’s gravitational force to travel to outer 
space. Escape velocity is the minimum speed required by an object i.e. satellite to 
escape from the gravitational force of the earth. The minimum velocity of satellite should 
be 11.2 km/sec. 
Q. 2. State with reasons whether the following sentences are true or false 
 
a. If a spacecraft has to be sent away from the influence of earth’s gravitational 
field, its velocity must be less than the escape velocity. 
b. The escape velocity on the moon is less than that on the earth. 
c. A satellite needs a specific velocity to revolve in a specific orbit. 
d. If the height of the orbit of a satellite increases, its velocity must also increase. 
Answer : (a) False 
 
Explanation: Space crafts should escape the earth’s gravitational force to travel to outer 
space. Escape velocity is the minimum speed required by an object i.e. satellite to 
escape from the gravitational force of the earth. So its speed should be more than the 
escape velocity. 
(b) True 
Explanation: The mass of moon is less than the mass of earth so its gravitational pull is 
less hence escape velocity on moon is less as compared to earth. 
(c) True 
Explanation: A satellite requires a specific velocity to revolve in a specific orbit called 
critical velocity which acts as a tangential direction to the orbit. 
(d) False 
Explanation: If the height of the orbit of a satellite increases, its velocity decreases. As 
tangential velocity of satellite is inversely proportional to the height of orbit of satellite 
from earth’s surface. 
V= v 
Where V = tangential velocity 
G = gravitational constant 
M = mass of earth 
R = radius of earth 
h = height of satellite above earth surface 
Q. 3. A. Answer the following question: 
 
What is meant by an artificial satellite? How are the satellites classified based on 
their functions? 
Answer : A manmade object revolves around the earth or any other planet in a fixed 
orbit is called an artificial satellite. 
Based on their function satellites are of various types- 
a. Weather satellite- Study and prediction of weather. 
b. Communication satellite – Establish communication between different location of the 
world. 
c. Broadcast satellite – Telecasting of tv programmes. 
d. Navigational satellite – Fix the location of any place on the earth’s surface. 
e. Military satellite – Collect information for security aspects. 
f. Earth observation satellite – Study of forests, deserts, oceans, polar ice etc. 
Q. 3. B. Answer the following question: 
 
What is meant by the orbit of a satellite? On what basis and how are the orbits of 
artificial satellites classified? 
Answer : An orbit is a regular, repeating path that satellite takes around the earth to 
revolve. Depending on the height of the satellite’s orbit above the earth surface, the 
orbit of satellites are classified as follows- 
 
i. High earth orbits- If the height of the satellite’s orbit above the earth’s surface is 
greater than or equal to 35780 km, the orbit is called high earth orbit. These satellites 
almost take 24 hours to complete one revolution. These are also called geosynchronous 
satellites. They are used in meterology, carry signals for telephone, TV, radio etc. 
ii. Medium earth orbits- If height of the satellite orbit above the earth’s surface is in 
between 2000 km and 35780 km the orbits are called medium earth orbits. 
iii. Low earth orbits – If the height of the satellite orbit above the earth’s surface is in 
between 180 km and 2000 km the orbits are called low earth orbits. They are used for 
scientific experiments and atmospheric studies. 
Q. 3. C. Answer the following question: 
 
Why are geostationary satellites not useful for studies of polar regions? 
Answer : Geostationary satellites orbit is above the equator so they are not useful for 
studies of polar regions. 
 
 
Q. 3. D. Answer the following question: 
 
What is meant by satellite launch vehicles? Explain a satellite launch vehicle 
developed by ISRO with the help of a schematic diagram. 
Answer : Satellite launch vehicles are used to place the satellites in their specific orbits. 
The function of this vehicle is based on Newton’s third law of motion. ISRO has 
developed PSLV [polar satellite launch vehicle]. It consists of an engine which uses 
solid fuel that provides initial thrust which provides certain velocity and takes it to certain 
height. There are four stages which uses solid and liquid fuel alternatively. Once the first 
stage fuel is used up the engine and first stage gets detached from the main body and 
falls into sea or unpopulated land. The weight got reduced and it moves with more high 
speed. Once the fuel in first stage is exhausted the fuel in second stage is ignited and 
so on. 
 
Page 5


Space Missions 
Exercise 
Q. 1. Fill in the blanks and explain the statements with reasoning: 
 
a. If the height of the orbit of a satellite from the earth surface is increased, the 
tangential velocity of the satellite will … 
b. The initial velocity (during launching) of the Mangalyaan, must be greater than 
…………..of the earth. 
Answer : (a) If the height of the orbit of a satellite from the earth surface is increased, 
the tangential velocity of the satellite will decreases. 
 
Explanation: As tangential velocity of satellite is inversely proportional to the height of 
orbit of satellite from earth’s surface. 
V= v 
Where V = tangential velocity 
G = gravitational constant 
M = mass of earth 
R = radius of earth 
h = height of satellite above earth surface 
(b) The initial velocity (during launching) of the Mangalyaan, must be greater 
than escape velocity of the earth. 
Explanation: Space crafts should escape the earth’s gravitational force to travel to outer 
space. Escape velocity is the minimum speed required by an object i.e. satellite to 
escape from the gravitational force of the earth. The minimum velocity of satellite should 
be 11.2 km/sec. 
Q. 2. State with reasons whether the following sentences are true or false 
 
a. If a spacecraft has to be sent away from the influence of earth’s gravitational 
field, its velocity must be less than the escape velocity. 
b. The escape velocity on the moon is less than that on the earth. 
c. A satellite needs a specific velocity to revolve in a specific orbit. 
d. If the height of the orbit of a satellite increases, its velocity must also increase. 
Answer : (a) False 
 
Explanation: Space crafts should escape the earth’s gravitational force to travel to outer 
space. Escape velocity is the minimum speed required by an object i.e. satellite to 
escape from the gravitational force of the earth. So its speed should be more than the 
escape velocity. 
(b) True 
Explanation: The mass of moon is less than the mass of earth so its gravitational pull is 
less hence escape velocity on moon is less as compared to earth. 
(c) True 
Explanation: A satellite requires a specific velocity to revolve in a specific orbit called 
critical velocity which acts as a tangential direction to the orbit. 
(d) False 
Explanation: If the height of the orbit of a satellite increases, its velocity decreases. As 
tangential velocity of satellite is inversely proportional to the height of orbit of satellite 
from earth’s surface. 
V= v 
Where V = tangential velocity 
G = gravitational constant 
M = mass of earth 
R = radius of earth 
h = height of satellite above earth surface 
Q. 3. A. Answer the following question: 
 
What is meant by an artificial satellite? How are the satellites classified based on 
their functions? 
Answer : A manmade object revolves around the earth or any other planet in a fixed 
orbit is called an artificial satellite. 
Based on their function satellites are of various types- 
a. Weather satellite- Study and prediction of weather. 
b. Communication satellite – Establish communication between different location of the 
world. 
c. Broadcast satellite – Telecasting of tv programmes. 
d. Navigational satellite – Fix the location of any place on the earth’s surface. 
e. Military satellite – Collect information for security aspects. 
f. Earth observation satellite – Study of forests, deserts, oceans, polar ice etc. 
Q. 3. B. Answer the following question: 
 
What is meant by the orbit of a satellite? On what basis and how are the orbits of 
artificial satellites classified? 
Answer : An orbit is a regular, repeating path that satellite takes around the earth to 
revolve. Depending on the height of the satellite’s orbit above the earth surface, the 
orbit of satellites are classified as follows- 
 
i. High earth orbits- If the height of the satellite’s orbit above the earth’s surface is 
greater than or equal to 35780 km, the orbit is called high earth orbit. These satellites 
almost take 24 hours to complete one revolution. These are also called geosynchronous 
satellites. They are used in meterology, carry signals for telephone, TV, radio etc. 
ii. Medium earth orbits- If height of the satellite orbit above the earth’s surface is in 
between 2000 km and 35780 km the orbits are called medium earth orbits. 
iii. Low earth orbits – If the height of the satellite orbit above the earth’s surface is in 
between 180 km and 2000 km the orbits are called low earth orbits. They are used for 
scientific experiments and atmospheric studies. 
Q. 3. C. Answer the following question: 
 
Why are geostationary satellites not useful for studies of polar regions? 
Answer : Geostationary satellites orbit is above the equator so they are not useful for 
studies of polar regions. 
 
 
Q. 3. D. Answer the following question: 
 
What is meant by satellite launch vehicles? Explain a satellite launch vehicle 
developed by ISRO with the help of a schematic diagram. 
Answer : Satellite launch vehicles are used to place the satellites in their specific orbits. 
The function of this vehicle is based on Newton’s third law of motion. ISRO has 
developed PSLV [polar satellite launch vehicle]. It consists of an engine which uses 
solid fuel that provides initial thrust which provides certain velocity and takes it to certain 
height. There are four stages which uses solid and liquid fuel alternatively. Once the first 
stage fuel is used up the engine and first stage gets detached from the main body and 
falls into sea or unpopulated land. The weight got reduced and it moves with more high 
speed. Once the fuel in first stage is exhausted the fuel in second stage is ignited and 
so on. 
 
Q. 3. E. Answer the following question: 
 
Why it is beneficial to use satellite launch vehicles made of more than one stage? 
Answer : The fuel forms a major portion of the total weight of the launch vehicle so 
vehicle has to carry a large weight with it. So to overcome these problems launch 
vehicles are made up of more than one stage so that the fuel in the stage when 
exhausted it gets detached from the main body step by step and weight is reduced so 
that it can move with high speed. 
Q. 4. Complete the following table. 
 
 
Answer : 
 
IRNSS: Fix the location of any place on the earth’s surface in terms of it precise latitude 
and longitude : Navigational Satellite.