Question:
Suppose a planet exists whose mass and radius both,are half those of Earth.Calculate the acceleration due to gravity on the surface of this planet.
Gravitation
Q 1.
State Kepler’s Laws of planetary motion. How did Newton guess inverse square law ?
Q 2.
A particle is dropped from a tower 180 m high.How long does it take to reach the ground ? What is the velocity when it touches the ground ? Take g =
Q 3.
Calculate the value of acceleration due to gravity on Moon. Given mass of Moon =
kg, radius of Moon = 1740 km
Q 4.
Why do sewing needles and all pins have a sharp pointed tip?
Q 5.
What is the value of ‘g’ at the centre of Earth ?
Q 6.
Which force is responsible for tides in the ocean at night ?
Q 7.
A boy on a clif£ 49 m high drops a stone.One second later,he throws a second stone after the first.They both hit the ground at the same time. With what speed did he throw the second stone ?
Q 8.
Two stones A and B are dropped from a multistoried building. A is dropped from 100 m and after some time B is dropped from 50 m height. Both of them reach the earth at the same time. Will they have equal velocity while reaching the ground ? Calculate and find out the answer (take g =10 m/s
2).
Q 9.
Fill in the blanks :
Every object in the universe ________ other bodies.
Q 10.
Can you calculate density of Earth from Newton’s law of gravitation ?
Q 11.
Suppose a planet exists whose mass and radius both,are half those of Earth.Calculate the acceleration due to gravity on the surface of this planet.
Q 12.
What do you mean by acceleration due to gravity ?
Q 13.
The mass of Earth is
kg and that of moon is
kg. If the distance between the Earth and the Moon is
km, calculate the force exerted by Earth on the Moon. Given G =
.
Q 14.
What do we call the gravitational force between the Earth and an object ?
Q 15.
State and explain universal law of gravitation given by Newton.What is the importance of this law
Q 16.
Who measured the value of G first time, experimentally?
Q 17.
Fill in the blanks :
________ of an object is the force of gravity acting on it.
Q 18.
At what height above the surface of the earth, the value of 'g' becomes 64% of its value at the surface of the earth. Take radius of the earth = 6400 km.
Q 19.
Calculate the force of gravitation between two objects of masses 80 kg and 1200 kg kept at a distance of 10 m from eachother.Given, G =
/
.
Q 20.
What is the importance of universal law of gravitation ?
Q 21.
What happens to 'g' experienced by a body when it moves up the earth's surface?
Q 22.
What is value of ‘g’ on Earth ?
Q 23.
What is the SI unit of weight ?
Q 24.
Distinguish between mass and weight.
Q 25.
Is weight a scalar quantity?
Q 26.
What are Plimsoll Lines?
Q 27.
Can a body have mass but no weight ?
Q 28.
Fill in the blanks :
When objects of different masses and sizes are dropped from same height would reach the ground at ______ (same time/different times), considering negligible air resistance.
Q 29.
Mass of an object is 10 kg. What is its weight on the Earth? (g = 9.8 m/s
2.)
Q 31.
Fill in the blanks :
Universal gravitational constant G = _____________.
Q 32.
A stone drops from the edge of the roof.It passes a window 2 m high in 0.1 s.How far is the roof above the top of the window
Q 33.
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 34.
Write down the equations of motion of objects under the influence of gravitational force of Earth.Explain the meaning of the symbols used.
Q 35.
Comment on application of Newton’s third law of motion to gravitation.Illustrate by examples.
Q 36.
Fill in the blanks :
The value of
g ________ (increases/decreases) as we go downwards from the earth's surface.
Q 37.
Why is G called the Universal Constant?
Q 38.
Does the force of attraction between two objects depend on the properties of intervening medium?
Q 39.
The weight of a man is 690N which contains 5.3 x 10
-3 m
3 of blood. Find (a) blood's weight. Take density of blood is 1060 kg/m
3 (b) express it as a percentage of body weight.
Q 40.
A car falls off a ledge and drops to the ground in 0.5 s.Let g =
(for simplifying the calculations).
(i) What is its speed on striking the ground ?
(ii) What is its average speed during 0.5 s ?
(iii) How high is the ledge from the ground ?
Q 41.
Why is the weight of an object on the Moon (l/6)th its weight on the Earth ?
Q 42.
How does the force of gravitation between two objects change when the distance between them is reduced to half ?
Q 43.
Why will a sheet of paper fall slower than one that is crumpled into a ball ?
Q 44.
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 45.
A stone is allowed to fall from the top of a tower 100 m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 25 m/s. Calculate when and where the two stones will meet
Q 46.
Does gravitational force between two objects depend on medium between them ?
Q 47.
Who gave three laws of planetary motion ?
Q 48.
Then why Is the Earth not seen moving towards the stone ?
Q 49.
Does value of ‘g’ vary from place to place on Earth ?
Q 50.
Where is ‘g' maximum, on the surface of Earth, above the surface or below the surface of Earth ?
