Questions on chapter Gravitation(Class-XI LEVEL)
GRAVITATION
1.
State and explain Newton’s law
of gravitation. Hence define Gravitational Constant G. What is its value in SI?
2.
Define acceleration due to
gravity. Discuss the variation of acceleration due to gravity with-i) the
altitude ii) the depth and iii) the shape of the earth.
3.
Discuss the variation of
acceleration due to gravity due to rotation of earth. What is the effect on g
at poles and equator of the earth due to rotation of earth?
4.
Derive the relation
g = GM/R2
for acceleration due to gravity of the
earth,where M and R are the mass and radius of the earth.
5.
Show that the acceleration of
free fall g at the surface of earth and the gravitational constant G are
related by the expression
g = 4/3 πρGR, where ρ is mean density of the earth and R, radius
of the earth.
6.
State and explain Kepler’s laws of
planetary motion.
7.
State Kepler’s laws of planetary
motion and deduce Newton’s law of gravitation from Kepler’s law.
8.
Discuss the effect of depth on
acceleration due to gravity. What is its value at the centre of the earth?
9.
Prove that the distance we have to
cover into earth below its surface is two times the distance we have to cover
above the surface to get the same change in the value of g .
1.
Show that Kepler’s second law follows
from the law of conservation of angular momentum.
1.
According to Newton ‘s law of
gravitation the apple and the earth
experience equal and opposite forces due to gravitation .but it is the apple
that falls towards the earth and not vice –versa. Why?
1.
If the diameter of earth becomes two
times its present and its mass remains unchanged; then how would the weight of
an object on the surface of the earth be affected?
1.
Does acceleration due to gravity
depend upon the mass of a planet? Explain.
1.
Do the forces of friction and other
contact forces arise due to gravitation attraction? if not,what is the origin
of these forces?
1.
Four equal masses are placed at the four
corners of a square. What is the intensity of gravitati onal field at the point
intersection of the diagonals of the square?
1.
Why do the stars appear
displaced away from the sun?
1.
Dose the change in
gravitational potential energy of a body between two points depend upon the
nature of path followed? Explain
1.
Define gravitational field and
intensity of gravitational field. Give its SI unit.
1.
Show that the gravitational
field and potential at any point on the surface of the earth are g and g R
respectively .The earth may be assumed to be a sphere of uniform density.
2.
Explain the terms gravitational
field and the gravitational potential energy.
2.
Define gravitational potential
and hence derive expression for it.
2 Define escape velocity. Derive
an expression for escape velocity of an object from the surface of a planet.
2.
Briefly explain why there is practically
no atmosphere on the sueface of the moon.
2.
Why dose hydrogen escape faster
from earth’s atmosphere than oxygen.
2.
The artificial satellite does
not have any fuel, but even then it remains orbiting around the earth. Why?
Explain.
2.
If a satellite going around the
earth suddenly loses weight, will there be a change in time period of the
satellite?
2.
Air friction increases the
velocity of the satellite. Explain.
2.
A satellite with kinetic energy
EK is revolving round the
earth in a circular orbit. How much more kinetic energy should be given, so
that it may just escape into the outer space?
2.
If T is the period of a
satellite revolving just above the surface of a plate, whose average density is
ρ, show that ρ T2 is a universal
constant.
3.
What is the difference between
ordinary and geostationary satellite?
3.
A body has a sense of
weightlessness in a satellite revolving around the earth. Why? Moon is a
satellite of earth, but there is no weightlessness condition on it. Explain.
3.
What do mean by geostationary
satellite and parking orbit? Show that height of a geostationary satellite from
the surface of earth is 36000km.
3.
What are lighter gaseous
elements, like hydrogen, helium etc., rare in the earth’s atmosphere?
Two artificial satellites of different masses are revolving round the earth at
the same altitude. When one will be moving faster? Justify your answer?
3.
Derive the expressions for-i)
kinetic energy ii) potential energy and iii) total energy of an artificial
satellite. Also draw their graphical variation with position.
3.
Show that everything become
weightless on earth’s surface (or, fly from earth) if rotational speed of earth is increased 17th
times of the present value.
3.
Show that the escape velocity
of earth is 11.2km/s. Show that moon will escape from earth’s atmosphere if its
speed is increased by 41.42 %.
3.
What do mean by weight of a
body? Show that weight of a body becomes zero at the centre of earth.
3.
What will the weight of a body
on the surface of earth, if earth is considered a hollow sphere?
3.
What do you mean by orbital
velocity of an artificial satellite? Derive and expression for it. Show that
time period and orbital velocity of a satellite don’t depends upon mass of the
satellite.
40.
Derive a relation between
orbital velocity and escape velocity of a satellite rotating very close to
earth.
41.
What do you mean by a polar
satellite? Write a short note on uses of a satellite.
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