Question:
Fill in the blanks :
According to the Heliocentric theory, the _____ is at centre and _______ move around it.
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 is the value of ‘g’ at the centre of Earth ?
Q 5.
What do we call the gravitational force between the Earth and an object ?
Q 6.
What do you mean by acceleration due to gravity ?
Q 7.
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 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.
Why do sewing needles and all pins have a sharp pointed tip?
Q 12.
Fill in the blanks :
Every object in the universe ________ other bodies.
Q 13.
Calculate the value of acceleration due to gravity on Moon. Given mass of Moon =
kg, radius of Moon = 1740 km
Q 14.
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 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.
Can a body have weight but no mass ?
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 gravitational force between the earth and the object is generally called ____________.
Q 21.
What is the gravitational acceleration of a spaceship at a distance equal to two Earth’s radius from the centre of the Earth ?
Q 22.
The distance between two objects is doubled. What happens to gravitational force between them
Q 23.
A stone falling towards Earth also attracts the Earth with the same force.Is it true ?
Q 24.
What are the Kepler Laws that govern the motion of the planets?
Q 26.
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 27.
Define weight? How it is related to mass?
Q 28.
Mass of an object is 10 kg. What is its weight on the Earth? (g = 9.8 m/s
2.)
Q 30.
Is mass a scalar quantity?
Q 31.
In what direction does the buoyant force on an object immersed in a liquid act?
Q 32.
Why is it difficult to hold a school bag having a strap made of a thin and strong string?
Q 33.
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 34.
Who gave three laws of planetary motion ?
Q 35.
Who explained the motion of planets around the Sun ?
Q 36.
State Kepler’s Laws of planetary motion.
Q 37.
Fill in the blanks :
Heliocentric model was proposed by ______.
Q 38.
Fill in the blanks :
The value of
g on the earth's surface is ______.
Q 39.
Fill in the blanks :
The value of
g ________ (increases/decreases) as we go upwards from the earth's surface.
Q 41.
Write the standard equations of motion when an object is thrown upwards with some initial velocity?
Q 42.
Name the scientist who identified the relation about force of gravitation. Name the law.
Q 43.
The pressure at the bottom of a filled glass (density = 1000 kg/m
3) of water is P. The water is taken out and the glass is filled with kerosene oil (density = 817.5 kg/m
3). Now the pressure at the bottom will be a. same as P b. smaller than P c. larger than P d. cannot be determined.
Q 44.
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 45.
A cuboid room has dimensions 50m x 15m x 3.5m. What is the mass of the air enclosed in the room if the density of air = 1.30 kg/m
3.
Q 46.
A solid block of density 6000 kg/m
3 weighs 0.6 kg in air. It is completely immersed in water of density 1000 kg/m
3. Calculate the apparent weight of the block in water and the buoyant force. (Take g = 10ms
-2)
Q 47.
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 48.
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 49.
What is the acceleration of free fall ?
Q 50.
Does Newton’s third law of motion apply to gravitational force ?
