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

Question # 1

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 # 2

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 # 3

What is the effect of the following on the gravitational acceleration
Mass of the freely falling body
Distance of the freely falling body from the center of the earth,(I>E> variation of "g" with altitude0 OR explain the variation in value of 'g' with altitude

Ans 1: We know that
g= GM_e/R²
^{where Me is mass of earth. Hence this equation does not include the mass of the freely fallingbody. The value of g does not depend on the mass of the body. All bodies either lighter or heavier fall freely with the same gravitationalacceleration. Thus mass has no effect on g}

Question # 4

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

Question # 5

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 # 6

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 # 7

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 # 8

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 # 9

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 # 10

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.

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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

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

State and explain gravitational field

What is the effect of the following on the gravitational accelerationMass of the freely falling bodyDistance of the freely falling body from the center of the earth,(I>E> variation of "g" with altitude0 OR explain the variation in value of 'g' with altitude

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

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

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.

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

What do you mean by artificial satellite

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

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

State and explain gravitational field

What is the effect of the following on the gravitational accelerationMass of the freely falling bodyDistance of the freely falling body from the center of the earth,(I>E> variation of "g" with altitude0 OR explain the variation in value of 'g' with altitude

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

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

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.

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

What do you mean by artificial satellite

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

What is the effect of the following on the gravitational acceleration
Mass of the freely falling body
Distance of the freely falling body from the center of the earth,(I>E> variation of "g" with altitude0 OR explain the variation in value of 'g' with altitude

What is the effect of the following on the gravitational acceleration
Mass of the freely falling body
Distance of the freely falling body from the center of the earth,(I>E> variation of "g" with altitude0 OR explain the variation in value of 'g' with altitude