Question:
Is weight a scalar quantity?
Answer:
No. It is a vector quantity.
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.
Fill in the blanks :
Weight of an object is the product of ______ and ________.
Q 8.
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 9.
Why do sewing needles and all pins have a sharp pointed tip?
Q 10.
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 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.
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 value of acceleration due to gravity on Moon. Given mass of Moon =
kg, radius of Moon = 1740 km
Q 15.
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 16.
Is weight a scalar quantity?
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.
Fill in the blanks :
________ of an object is the force of gravity acting on it.
Q 19.
Fill in the blanks :
The gravitational force between the earth and the object is generally called ____________.
Q 20.
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 21.
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 22.
On earth,value of G =
.What is its value on moon,where g is nearly
th that of earth ?
Q 23.
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 24.
Fill in the blanks :
Heliocentric model was proposed by ______.
Q 25.
What was heliocentric theory? Who proposed this?
Q 26.
What are the Kepler Laws that govern the motion of the planets?
Q 27.
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 31.
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 33.
Name the scientist who identified the relation about force of gravitation. Name the law.
Q 34.
Is mass a scalar quantity?
Q 36.
Fill in the blanks :
Motion of body with constant speed in a circular path is called ______________.
Q 37.
Fill in the blanks :
The SI unit of mass is ______.
Q 38.
Fill in the blanks :
It is the ____________ of the earth, which holds our atmosphere in place.
Q 39.
Why does an object float or sink when placed on the surface of the water?
Q 40.
What are Plimsoll Lines?
Q 41.
Why will a sheet of paper fall slower than one that is crumpled into a ball?
Q 42.
The volume of 50 g of a substance is 20 cm
3. If the density of water is 1 g cm
-3, will the substance float or sink?
Q 43.
As you climb up a mountain, your ears “pop” because of the changes in atmospheric pressure. In which direction, outward or inward, does your eardrum move when you climb up?
Q 44.
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 45.
What is the gravitational acceleration of a spaceship at a distance equal to two Earth’s radius from the centre of the Earth ?
Q 46.
Mass of an object is 10 kg. What is its weight on Earth ?
Q 47.
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 48.
What are the differences between the mass of an object and its weight ?
Q 49.
How does the force of gravitation between two objects change when the distance between them is reduced to half ?
Q 50.
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.)
