Question:
Fill in the blanks :
The value of g ________ (increases/decreases) as we go downwards from the earth's surface.
Gravitation
Q 1.
State Kepler’s Laws of planetary motion. How did Newton guess inverse square law ?
Q 2.
Why do sewing needles and all pins have a sharp pointed tip?
Q 3.
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 4.
Calculate the value of acceleration due to gravity on Moon. Given mass of Moon =
kg, radius of Moon = 1740 km
Q 5.
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 6.
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 7.
Fill in the blanks :
Every object in the universe ________ other bodies.
Q 8.
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 9.
What is the value of ‘g’ at the centre of Earth ?
Q 10.
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 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.
What do you mean by acceleration due to gravity ?
Q 13.
Which force is responsible for tides in the ocean at night ?
Q 14.
State and explain universal law of gravitation given by Newton.What is the importance of this law
Q 15.
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 16.
What do we call the gravitational force between the Earth and an object ?
Q 17.
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 18.
Can you calculate density of Earth from Newton’s law of gravitation ?
Q 19.
Fill in the blanks :
________ of an object is the force of gravity acting on it.
Q 20.
Fill in the blanks :
The value of
g at poles is ______ (lower/higher) than its value at the equator.
Q 22.
Fill in the blanks :
Heliocentric model was proposed by ______.
Q 23.
Who measured the value of G first time, experimentally?
Q 24.
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 25.
What is the gravitational acceleration of a spaceship at a distance equal to two Earth’s radius from the centre of the Earth ?
Q 26.
Fill in the blanks :
The value of
g on the earth's surface is ______.
Q 27.
What happens to 'g' experienced by a body when it moves up the earth's surface?
Q 28.
Write the standard equations of motion when an object is thrown upwards with some initial velocity?
Q 30.
Fill in the blanks :
Assuming negligible air drag, if a steel ball and a table tennis ball are dropped from a height of 100 metres, both will reach the ground at ________ time(s). (same/different)
Q 31.
What is the importance of universal law of gravitation ?
Q 32.
Why will a sheet of paper fall slower than one that is crumpled into a ball ?
Q 33.
The distance between two objects is doubled. What happens to gravitational force between them
Q 34.
What is value of ‘g’ on Earth ?
Q 35.
How are gravitation and gravity related ?
Q 36.
Can you calculate mass of Earth from Newton’s law of gravitation ?
Q 37.
State and explain universal law of gravitation.What is its importance ?
Q 38.
Fill in the blanks :
Weight of an object is the product of ______ and ________.
Q 39.
What are the Kepler Laws that govern the motion of the planets?
Q 40.
When a ball is thrown upwards, it falls back to the ground. Name the force which makes it fall.
Q 41.
Fill in the blanks :
The force of gravity _________ with altitude. It also varies on the surface of the earth, _________ from poles to the equator.
Q 42.
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 43.
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 44.
Write the formula to find the magnitude of the gravitational force between the Earth and an object on the surface of the Earth.
Q 45.
Why is the weight of an object on the Moon (l/6)th its weight on the Earth ?
Q 46.
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 47.
What is the source of centripetal force that a planet requires to revolve around the Sun ? On what factors does that force depend ?
Q 48.
What is the SI unit of mass ?
Q 49.
Why don’t two objects move towards each other due to gravitational pull between them ?
Q 50.
On earth,value of G =
.What is its value on moon,where g is nearly
th that of earth ?
