Question:
Fill in the blanks :
The value of g ________ (increases/decreases) as we go upwards from the earth's surface.
Gravitation
Q 1.
State Kepler’s Laws of planetary motion. How did Newton guess inverse square law ?
Q 2.
Calculate the force of gravitation between the Earth and the Sun,given that the mass of the Earth =
kg and mass of the Sun =
kg. The average distance between the two is
m.
Q 3.
Can you calculate density of Earth from Newton’s law of gravitation ?
Q 4.
What do we call the gravitational force between the Earth and an object ?
Q 5.
What is the value of ‘g’ at the centre of Earth ?
Q 6.
What do you mean by acceleration due to gravity ?
Q 7.
Why do sewing needles and all pins have a sharp pointed tip?
Q 8.
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 9.
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 10.
Fill in the blanks :
Weight of an object is the product of ______ and ________.
Q 11.
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 12.
Fill in the blanks :
Every object in the universe ________ other bodies.
Q 13.
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 14.
Calculate the force of gravitation between the earth and the Sun, given that the mass of the earth = 6 × 10
24 kg and of the Sun = 2 × 10
30 kg. The average distance between the two is 1.5 × 10
11 m.
Q 15.
Is weight a scalar quantity?
Q 16.
Fill in the blanks :
________ of an object is the force of gravity acting on it.
Q 17.
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 18.
Calculate the value of acceleration due to gravity on Moon. Given mass of Moon =
kg, radius of Moon = 1740 km
Q 19.
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 20.
Fill in the blanks :
The SI unit of mass is ______.
Q 21.
Fill in the blanks :
The gravitational force between the earth and the object is generally called ____________.
Q 22.
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 23.
What is the gravitational acceleration of a spaceship at a distance equal to two Earth’s radius from the centre of the Earth ?
Q 24.
A stone falling towards Earth also attracts the Earth with the same force.Is it true ?
Q 25.
On earth,value of G =
.What is its value on moon,where g is nearly
th that of earth ?
Q 26.
Fill in the blanks :
Heliocentric model was proposed by ______.
Q 27.
Fill in the blanks :
The value of
g on the earth's surface is ______.
Q 28.
How is gravitational force of attraction between two bodies affected if(i) Mass of both bodies is doubled.(ii) Distance between them is halved.
Q 29.
Define weight? How it is related to mass?
Q 30.
Mass of an object is 10 kg. What is its weight on the Earth? (g = 9.8 m/s
2.)
Q 32.
Is mass a scalar quantity?
Q 34.
Why does an object float or sink when placed on the surface of the water?
Q 35.
What are Plimsoll Lines?
Q 36.
Why will a sheet of paper fall slower than one that is crumpled into a ball?
Q 37.
The volume of a 500 g sealed packet is 350 cm
3. Will the packet float or sink in water if the density of water is 1 g cm
-3? What will be the mass of the water displaced by this packet?
Q 38.
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 39.
What are the differences between the mass of an object and its weight ?
Q 40.
What is the magnitude of the gravitational force between the Earth and a 1 kg on its surface ? (Mass of the Earth Is
kg and radius of the Earth is
m.)
Q 41.
Two objects of masses
having the same size are dropped simultaneously from heights
respectively.Find out the ratio of time they would take in reaching the ground.Will this ratio remain the same if (1) one of the objects is hollow and the other one is solid and (ii) both of them are hollow,size remaining the same in each case.Give reason.
Q 42.
The distance between two objects is doubled. What happens to gravitational force between them
Q 43.
What is the usual shape of orbits of planets around the Sun ?
Q 44.
Does Newton’s third law of motion apply to gravitational force ?
Q 45.
Can a body have mass but no weight ?
Q 46.
How are gravitation and gravity related ?
Q 47.
State and explain universal law of gravitation given by Newton.What is the importance of this law
Q 48.
Define g and G.Establish relation between them.
Q 49.
Fill in the blanks :
Geocentric model i.e. the Earth is the orbital centre of all celestial bodies was proposed by _____.
Q 50.
Fill in the blanks :
According to the Heliocentric theory, the _____ is at centre and _______ move around it.
