Matric Part 1/9th Class Physics Chapter 5 Long Question With Answer for Unit 5 Gravitation

Question # 1

State and explain gravitational field

Ans 1: Gravitational pull of earth acting on the body whether the body is in contact with earth or not is called the field force and the are for this force around the earth is called gravitational field
Ans 2: For example: the velocity of a body, thrown up, goes on decreasing while on return its velocity goes on increasing. It is due to the gravitational pull earth acting on the body, which is a field force. It is assumed that a gravitational field exists all around the earth. This field is directed towards the center of the earth. The gravitational field becomes weaker and weaker as we go farther and farther away from the earth
Ans 3: Gravitational field strength: in the gravitational field of the earth, the gravitational force per unit mass is called the gravitational field strength of the earth. At any place its value is equal to the value of g at that point

Question # 2

Q no: 6 (A) State Law of gravitation and derived the equation.

Ans 1: 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.
F x m1m2
F x 1/d²
F x m1m2/d²
F= Gm1m2/d²

Question # 3

Q no(B) Define satellites. Find the orbital velocity of on artificial satellites.

Ans 1: Satellite:
An object that revolves around a planet is called satellite . The moon revolves around the earth as moon is a natural satellite of the earth.
Scientists have sent many objects into space Some of these objects revolve around the earth. These are called artificialsatalites. Most of the artificial satallite orbiting around the Earth are usedfor communication purposes .Artificial satellites carry instruments or passengers to perform experiments in space.
Large number of artificial satellites have been launched in different orbits around the Earth.

Question # 4

Describe the motion of artificial satellite and derive the formula for the orbital speed of the artificial satellite

Ans 1: Artificial satellite: Artificial satellites are launched for space research and telecommunication. With their help, we are able to enjoy live coverage of cricket matches, Olympic games and many other programs directly on our television sets.
Artificial satellites keep on revolving around the earth in different geo stationary satellite orbits with uniform speed due to gravitational force

Question # 5

Q no: (B) A polar satellite is launched at 850 km above earth. Find its orbital speed.

Ans 1: Solution:
Height= 850 km
= 850 x 1000m
850000m = 8.5 x 10⁵m
orbital speed = v=?
V=√GMe/(R+h)
=√6.673 x 10-¹¹ x 6 x 10²⁴/(6.4 x 10⁶ + 8.5 x 10⁵ )
= 743.13 ms-¹

Question # 6

Determine the mass of earth using Newtons law of gravitation

Ans 1: Mass of earth: the mass of earth can be calculated by using Newtons law of gravitationExplanation; consider a body of mass m is placed on the surface of the earth. The distance between the center of the body and the earth is R which is equal to radius of the earth. The mass of earth is Me.We know that the force with which the earth attracts a body on its surface towards its center is equal to the weight of the body

Question # 7

Q no 7 (A) Explain the motion of Artificial satellites.

Ans 1: A satellite requires centripetal force of attraction between the salellite and the Earth provides the necessary centripetal force.
Consider a satellite of mass revolving round the earth at an altitude h in a orbit of radian to with orbital velocity Vo The necessary centripetal force required is given by equation
fc = mv²o/r_o
Fc = w^' = mg_n
mg_hmv²o/r_o
V_o²= g_h ro
vo= √g_hro
V_o= √g_n(R+h)
Equation ( 5.10) gives the velocity which a satellite must possess when launched in an orbit of radius r_o=9R+h) around the Earth
R+h= R
g_n = g
v_o=√gR
A satellite revolving around very close to the Earth has speed V_o nearly 8kms-¹ or 29000 kmh-¹

Question # 8

Q no: 5 (A) What ismeant by the force of gravitation? Also explain the law of gravitation.

Ans 1: everybody in the universeattracts 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.

According to the law of gravitation the gravitationalforce of attraction F with which the two masses m1 and m2 separated by a distance `d' attract each other is given by:
F x m1m2
F x 1/d²
F x m1m2/d²
F=G m1m2/d²

Question # 9

What do you mean by artificial satellite

Ans 1: Satellite: an object that revolves around a planet is called a satellite
Natural satellite: the moon revolves around the earth so moon is a natural satellite of the earth
Artificial; scientists have sent many objects into space. Some of these objects revolve around the earth. These are called artificial satellites.
Ans 2: Uses of artificial satellite: Most of the artificial satellites , orbiting around the earth are used for communication purpose.
Artificial satellites carry instruments or passengers to preform experiments in space. Large number of artificial satellites have been launched in different orbits around the earth.
Dish antennas sending and receiving the signals from them have fixed direction depending upon their location on the earth.

Question # 10

Q no: (B) A polar satellite is launched at 850 km above earth. Find its orbital speed.

Ans 1: Solution:
Height= 850 km
= 850 x 1000m
850000m = 8.5 x 10⁵m
orbital speed = v=?
V=√GMe/(R+h)
=√6.673 x 10-¹¹ x 6 x 10²⁴/(6.4 x 10⁶ + 8.5 x 10⁵ )
= 743.13 ms-¹

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Matric Part 1/9th Class Physics Chapter 5 Long Question With Answer for Unit 5 Gravitation

9th Class English Medium Subjects

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Online Long Questions For Chapter 5 "9th Class Physics Chapter 5 Long Question Preparation "

Physics (New Book) - 9th Class Physics Chapter 5 Long Question Preparation

State and explain gravitational field

Q no: 6 (A) State Law of gravitation and derived the equation.

Q no(B) Define satellites. Find the orbital velocity of on artificial satellites.

Describe the motion of artificial satellite and derive the formula for the orbital speed of the artificial satellite

Q no: (B) A polar satellite is launched at 850 km above earth. Find its orbital speed.

Determine the mass of earth using Newtons law of gravitation

Q no 7 (A) Explain the motion of Artificial satellites.

Q no: 5 (A) What ismeant by the force of gravitation? Also explain the law of gravitation.

What do you mean by artificial satellite

Q no: (B) A polar satellite is launched at 850 km above earth. Find its orbital speed.

Prepare Complete Set Wise Questions For Chapter 5 "9th Class Physics Chapter 5 Long Question Preparation "

Set 1

9th Class Physics Chapter 5 Long Question Preparation - Set 1

State and explain gravitational field

Q no: 6 (A) State Law of gravitation and derived the equation.

Q no(B) Define satellites. Find the orbital velocity of on artificial satellites.

Describe the motion of artificial satellite and derive the formula for the orbital speed of the artificial satellite

Q no: (B) A polar satellite is launched at 850 km above earth. Find its orbital speed.

Determine the mass of earth using Newtons law of gravitation

Q no 7 (A) Explain the motion of Artificial satellites.

Q no: 5 (A) What ismeant by the force of gravitation? Also explain the law of gravitation.

What do you mean by artificial satellite

Q no: (B) A polar satellite is launched at 850 km above earth. Find its orbital speed.

9th class Physics Chapter 5 Long Q's (English Medium)

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