Gravitation: 9th Class Physics Chapter 5 Solved MCQs
1. The value of “g” at a height of Earth’s radius above the surface of the Earth is (A) 2g (B) ½ g
(C) 1/3 g
(D) ¼ g
2. Earth’s gravitational force vanishes at:
(A) 6400 km
(B) Infinity
(C) 42300 Km
(D) 1000 km
3. Moon completes its one revolution around the earth in:
(A) One day
(B) 17.3 days
(C) 22.3 days
(D) 27.3 days
4. The orbital speed of a low orbit satellite is:
(A) Zero
(B) 8 Km/s
(C) 800 ms-¹
(D) 8000 ms-¹
5. The value of “g” at the moon is:
(A) 1.7 ms-²
(B) 1.6 ms-²
(C) 10 ms-²
(D) 9.8 ms-²
6. A force which is inversely proportional to the square the distance between the centers of bodies is
(A)Frictional force
(B) Centrifugal force
(C) Centripetal force
(D) Gravitational force
7. The centre of gravity of an irregular shaped body can be found with the help of
(A) Screw gauge
(B) Plumbline
(C) Meter rod
(D) Wedge
8. Value of “g” increases with the:
(A) Increase in the mass of the body
(B) Increase in altitude
(C) Decrease in altitude
(D) None of the above
9. The value of “g” at a height one Earth’s radius above the surface of the Earth is:
(A) 2 g
(B) ½ g
(C) 1/3 g
(D) ¼ g
10. The value of “g” on the moon’s surface is 1.6ms-². What will be the weight of a 100 kg body on the surface of the moon?
(A) 100 N
(B) 160 N
(C) 1000 N
(D) 1600 N
This is a simple post about Physics Notes of 9 Class. This post Contains 9th Class Physics Chapter 5 Notes – Short Questions and Numericals for the students. You can add these short questions to the list of your preparation for exams.
9th Class Physics Chapter 5 Notes – Short Questions and Numericals
Q.1 What is meant by gravitational field strength?
Ans. In the gravitational field of the Earth, the gravitational force per unit mass is called the gravitational field strength of the earth.
Q.2: What are artificial satellites?
Ans. Scientists have sent many objects into space. Some of these objects revolve around the
Earth. These are called artificial satellites.
Q.3: Write the equation from which calculate the mass of earth.
Ans. Me = R² g/G
Q.4: Define the law of gravitation.
Ans. Everybody in the universe attracts every other body with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centres.
Q.5: What is the height and speed of Geo-Stationary Satellite from the surface of the earth?
Ans. The height of a geostationary satellite is about 42300 km from the surface of the Earth. Its velocity with respect to Earth is zero.
Q.6: What is meant by the force of gravitation?
Ans. A force due to which everybody of the universe attracts every other body it is called the force of gravitation.
Q.7: Why communication satellites are stationed at geostationary orbits?
Ans. The satellites in “geostationary orbits” remain all the time, in front of saws part of Earth so that direction of receiver’s.
Q.8: What is meant by satellite?
Ans. An object that revolves around a planet is called a satellite.
Q.9: Write the formula of artificial satellite orbital speed.
Ans. 
Q.10: What is meant by Global Positioning System (GPS)?
Ans. Global Positioning System (GPS) is a satellites navigation system. It helps us to find the exact position of an object anywhere on the land, on the sea or in the air. GPS consists of 24 Earth satellites. These satellites revolve around the Earth twice a day with a speed of 3.87 kms-¹.
