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

9th Class Physics chapter 5 Long Questions

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

Question # 1

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 # 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

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 # 4

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 # 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

How will you relate law of gravitation and Newtons third law of motion

Ans 1: in law of gravitation it is to be noted that mass m1 attracts m2 towards it with a force F while mass m2 attract m1 towards it with a force of the same magnitude F but in opposite direction. If the force acting on m1 is considered as action then the force acting on m2 will be the reaction . We can say that the action and reaction due to force of gravitation are equal in magnitude but opposite in direction. This is in consistent with newtons third law of motion which states , to every action there is always an equal but opposite reaction

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

State and explain Newtons law of gravitation. Also derive its equation

Ans 1: Law of gravitation: Every object in the universe attracts every other object with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
Ans 2: Note; we don not feel the gravitational force between different objects around us because it is very small. However we can observe the effect of gravitational force easily, if the mass of one or both objects is very large . Since the mass of earth is very large, it attracts nearby objects with a significant force. The weight of an object on the earth is a result of the gravitational fore between the two masses.

Question # 10

Q no: 6 (B) Calculate the value of g at a height of 3600 km above the surface of the Earth.

Ans 1: Solution:
g_n =?
h = 3600km = 3600 x 1000m
R = 6400 x 10³ m
G = 6.673 x 10-¹¹ Nm²kg-²
Me = 6x 10²⁴ kg
g = GMe/R²
g_n = Gme/(R+h)²
6.673 x10-¹¹ x 6 x 10²⁴/6400 x10³ + 3600 x10³
g_n = 4ms-²

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

Set 1

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

Question # 1

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 # 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

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 # 4

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 # 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

How will you relate law of gravitation and Newtons third law of motion

Ans 1: in law of gravitation it is to be noted that mass m1 attracts m2 towards it with a force F while mass m2 attract m1 towards it with a force of the same magnitude F but in opposite direction. If the force acting on m1 is considered as action then the force acting on m2 will be the reaction . We can say that the action and reaction due to force of gravitation are equal in magnitude but opposite in direction. This is in consistent with newtons third law of motion which states , to every action there is always an equal but opposite reaction

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

State and explain Newtons law of gravitation. Also derive its equation

Ans 1: Law of gravitation: Every object in the universe attracts every other object with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
Ans 2: Note; we don not feel the gravitational force between different objects around us because it is very small. However we can observe the effect of gravitational force easily, if the mass of one or both objects is very large . Since the mass of earth is very large, it attracts nearby objects with a significant force. The weight of an object on the earth is a result of the gravitational fore between the two masses.

Question # 10

Q no: 6 (B) Calculate the value of g at a height of 3600 km above the surface of the Earth.

Ans 1: Solution:
g_n =?
h = 3600km = 3600 x 1000m
R = 6400 x 10³ m
G = 6.673 x 10-¹¹ Nm²kg-²
Me = 6x 10²⁴ kg
g = GMe/R²
g_n = Gme/(R+h)²
6.673 x10-¹¹ x 6 x 10²⁴/6400 x10³ + 3600 x10³
g_n = 4ms-²

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Physics

5th Unit

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

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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

9th Class Urdu Medium Subjects

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

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

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

State and explain gravitational field

Determine the mass of earth using Newtons law of gravitation

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

How will you relate law of gravitation and Newtons third law of motion

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.

State and explain Newtons law of gravitation. Also derive its equation

Q no: 6 (B) Calculate the value of g at a height of 3600 km above the surface of the Earth.

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

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

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

State and explain gravitational field

Determine the mass of earth using Newtons law of gravitation

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

How will you relate law of gravitation and Newtons third law of motion

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.

State and explain Newtons law of gravitation. Also derive its equation

Q no: 6 (B) Calculate the value of g at a height of 3600 km above the surface of the Earth.

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

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