Question:
Compare gravitational force between light objects and heavy objects.
Answer:
Refer to Art 3.6,Page 145.
Gravitation
Q 1.
The following figure shows four containers containing a liquid at the same height. Rank them according to the pressure exerted by the liquid on the bottom of the containers in ascending order.
a. 1, 2, 3, 4 b. 4. 3, 1, 2 c. 3, 4, 1, 2 d. same pressure in each case.
Q 2.
What is the SI unit of weight ?
Q 3.
Fill in the blanks :
The value of G was found out by _______ by using a ________.
Q 4.
What is the source of centripetal force that a planet requires to revolve around the Sun ? On what factors does that force depend ?
Q 5.
Why don’t two objects move towards each other due to gravitational pull between them ?
Q 6.
Fill in the blanks :
The value of
g ________ (increases/decreases) as we go upwards from the earth's surface.
Q 7.
What do you mean by free fall ?
Q 8.
What is the SI unit of mass ?
Q 9.
Can you calculate mass of Earth from Newton’s law of gravitation ?
Q 10.
Define g and G.Establish relation between them.
Q 11.
What are the differences between the mass of an object and its weight ?
Q 12.
What is the acceleration of free fall ?
Q 13.
A stone is thrown vertically upward with an initial velocity of 40 m/s.Taking g =
,find the maximum height reached by the stone.What is the net displacement and the total distance covered by the stone ?
Q 14.
Does Newton’s third law of motion apply to gravitational force ?
Q 15.
A body is just dropped from a height What is its initial velocity ?
Q 16.
Can a body have weight but no mass ?
Q 17.
How are gravitation and gravity related ?
Q 18.
A body weighs 10 kg on the surface of earth.What would be its mass and weight at the centre of earth ?
Q 19.
Fill in the blanks :
Acceleration due to gravity (g) is _______ (dependent/independent) of mass.
Q 20.
Why is G called the Universal Constant?
Q 21.
Gravitational force acts on all objects in proportion to their masses. Why then, a heavy object does not fall faster than a light object?
Q 22.
A ball is thrown upwards from the ground of a tower with a speed of 20 m/s. There is a window in the tower at the height of 15m from ground. How many times and when will the ball pass the window? (g = 10 m/s
2)
Q 23.
The tangential velocity of a planet or moon moving in a circle is at a right angle to ____________. (fill in the blank)
Q 24.
Fill in the blanks :
The SI unit of weight is _______.
Q 26.
Why is it difficult to hold a school bag having a strap made of a thin and strong string?
Q 27.
Two bodies A and B having masses 2 kg and 4 kg respectively are separated by 2 m.Where should a body of mass 1 kg be placed so that the gravitational force on this body due to bodies A and B is zero ?
Q 28.
Mass of an object is 10 kg. What is its weight on Earth ?
Q 29.
A ball is thrown up with a speed of 15 m/s.How high will it go before it begins to fall ? Take g=
Q 30.
How does the force of gravitation between two objects change when the distance between them is reduced to half ?
Q 31.
The Earth and the Moon are attracted to each other by gravitational force. Does the Earth attract the Moon with a force that is greater or smaller or the same as the force with which the Moon attracts the Earth ? Why ?
Q 32.
What is the usual shape of orbits of planets around the Sun ?
Q 33.
Then why Is the Earth not seen moving towards the stone ?
Q 34.
Where is ‘g' maximum, on the surface of Earth, above the surface or below the surface of Earth ?
Q 35.
What is the weight of a body of mass 1 kg on Earth ?
Q 36.
In free fall, will heavier objects accelerate more than light ones ?
Q 37.
State Kepler’s Laws of planetary motion.
Q 38.
Explain what is meant by ‘free fall’and acceleration due to gravity.
Q 39.
Comment on application of Newton’s third law of motion to gravitation.Illustrate by examples.
Q 40.
In Fig.,the line that joins a planet to the sun sweeps out areas
,
in time intervals 6 weeks,3 weeks and 2 weeks respectively.How are
,
realted ?
Q 41.
Fill in the blanks :
The value of
g ________ (increases/decreases) as we go downwards from the earth's surface.
Q 42.
An object moves in a circular motion due to centripetal force, acting towards the center. The moon also rotates around the earth? Does centripetal force acts on it? Why does the moon not fall on the earth?
OR
Q:If the moon attracts the earth, why does the earth not move towards the moon?
Q 43.
The earth and the moon are attracted to each other by gravitational force. Does the earth attract the moon with a force that is greater or smaller or the same as the force with whichthe moon attracts the earth? Why?
Q 44.
Does Law of gravitation obey Newton's third law of motion?
Q 45.
Fill in the blanks :
The acceleration which causes changes only in direction of the velocity of a body is called __________ and it is always directed ___________ the circle.
Q 46.
Fill in the blanks :
A body is said to be in _______ when only gravity acts on it.
Q 47.
Fill in the blanks :
The SI unit of mass is ______.
Q 48.
Fill in the blanks :
It is the ____________ of the earth, which holds our atmosphere in place.
Q 49.
Fill in the blanks :
Universal gravitational constant G = _____________.
Q 50.
State Archimedes’ Principle. Based on this principle, write its two applications.
