Question:
What is value of ‘g’ on Earth ?
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.
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 6.
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 7.
Fill in the blanks :
________ of an object is the force of gravity acting on it.
Q 8.
Why do sewing needles and all pins have a sharp pointed tip?
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.
What is the value of ‘g’ at the centre of Earth ?
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.
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 14.
What do you mean by acceleration due to gravity ?
Q 15.
Calculate the value of acceleration due to gravity on Moon. Given mass of Moon =
kg, radius of Moon = 1740 km
Q 16.
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 17.
Write the standard equations of motion when an object is thrown upwards with some initial velocity?
Q 18.
What is the gravitational acceleration of a spaceship at a distance equal to two Earth’s radius from the centre of the Earth ?
Q 19.
Distinguish between gravitation and gravity.
Q 20.
Fill in the blanks :
Weight of an object is the product of ______ and ________.
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.
The distance of planet Jupiter from the sun is 5-2 times that of Earth.Find the period of revolution of Jupiter around sun.
Q 24.
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 25.
State and explain universal law of gravitation.What is its importance ?
Q 26.
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 27.
Which force is responsible for tides in the ocean at night ?
Q 28.
How are gravitation and gravity related ?
Q 29.
Explain what is meant by ‘free fall’and acceleration due to gravity.
Q 30.
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 31.
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 32.
You find your mass to be 42 kg on a weighing machine. Is your mass more or less than 42 kg?
Q 33.
A force of 20 N acts upon a body whose weight is 9.8 N.What is the mass of the body and how much is its acceleration ?
Q 34.
What is the source of centripetal force that a planet requires to revolve around the Sun ? On what factors does that force depend ?
Q 35.
Which force revolves Moon around Earth ?
Q 36.
Which force accelerates a body in free fall ?
Q 37.
Does Newton’s third law of motion apply to gravitational force ?
Q 38.
Does value of ‘g’ vary from place to place on Earth ?
Q 39.
A body is just dropped from a height What is its initial velocity ?
Q 40.
On earth,value of G =
.What is its value on moon,where g is nearly
th that of earth ?
Q 41.
Fill in the blanks :
The force which keeps the object moving in a circular path is called _____ force. It always acts towards the _____.
Q 42.
Fill in the blanks :
The force of attraction between two objects is ______ proportional to the product of their masses and _____ proportional to the square of a distance between them.
Q 43.
Fill in the blanks :
Kepler's Law of ______ states that a line that connects a planet to the Sun sweeps out equal ______ in the plane of the planet's orbit in _____time intervals.
Q 44.
Fill in the blanks :
The mass of the earth is ________ kg.
Q 45.
Fill in the blanks :
The value of
g ________ (increases/decreases) as we go downwards from the earth's surface.
Q 46.
Who measured the value of G first time, experimentally?
Q 47.
Does Law of gravitation obey Newton's third law of motion?
Q 48.
Define weight? How it is related to mass?
Q 49.
A stone is released from the top of a tower of height 19.6 m. Calculate its final velocity just before touching the ground.
Q 50.
Fill in the blanks :
All other variables remaining constant, the force of gravitation is ________ proportional to the square of distance between the two objects.
