Question:
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 =
Gravitation
Q 1.
State Kepler’s Laws of planetary motion. How did Newton guess inverse square law ?
Q 2.
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 3.
Calculate the value of acceleration due to gravity on Moon. Given mass of Moon =
kg, radius of Moon = 1740 km
Q 4.
Why do sewing needles and all pins have a sharp pointed tip?
Q 5.
What is the value of ‘g’ at the centre of Earth ?
Q 6.
Which force is responsible for tides in the ocean at night ?
Q 7.
Can you calculate density of Earth from Newton’s law of gravitation ?
Q 8.
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 9.
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 10.
Fill in the blanks :
Every object in the universe ________ other bodies.
Q 11.
What do you mean by acceleration due to gravity ?
Q 12.
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 13.
What do we call the gravitational force between the Earth and an object ?
Q 14.
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 15.
State and explain universal law of gravitation given by Newton.What is the importance of this law
Q 16.
Fill in the blanks :
________ of an object is the force of gravity acting on it.
Q 17.
Who measured the value of G first time, experimentally?
Q 18.
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 19.
What is the importance of universal law of gravitation ?
Q 20.
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 21.
What happens to 'g' experienced by a body when it moves up the earth's surface?
Q 22.
What is value of ‘g’ on Earth ?
Q 24.
What are Plimsoll Lines?
Q 25.
Is weight a scalar quantity?
Q 26.
What is the SI unit of weight ?
Q 27.
Distinguish between mass and weight.
Q 28.
Why is G called the Universal Constant?
Q 29.
Mass of an object is 10 kg. What is its weight on the Earth? (g = 9.8 m/s
2.)
Q 30.
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 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.
A body is just dropped from a height What is its initial velocity ?
Q 33.
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 34.
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 35.
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 36.
Then why Is the Earth not seen moving towards the stone ?
Q 37.
State and explain universal law of gravitation.What is its importance ?
Q 38.
Fill in the blanks :
When objects of different masses and sizes are dropped from same height would reach the ground at ______ (same time/different times), considering negligible air resistance.
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.
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 42.
Which force accelerates a body in free fall ?
Q 43.
Who gave three laws of planetary motion ?
Q 44.
A stone falling towards Earth also attracts the Earth with the same force.Is it true ?
Q 45.
Does value of ‘g’ vary from place to place on Earth ?
Q 46.
Distinguish between gravitation and gravity.
Q 47.
Write down the equations of motion of objects under the influence of gravitational force of Earth.Explain the meaning of the symbols used.
Q 48.
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 49.
Fill in the blanks :
The value of
g on the earth's surface is ______.
Q 50.
An object moves in a circular motion due to centripetal force, acting towards the center. The moon also rotates around the earth? Does centripetal force acts on it? Why does the moon not fall on the earth?
OR
Q:If the moon attracts the earth, why does the earth not move towards the moon?
