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Physics
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Gravitation
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Hard Questions
Gravitation
Physics
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JEE Mains
NEET
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Hard Qs
>
A planet in a distant solar system is
1
0
times more massive than the earth and its radius is
1
0
times smaller. Given that the escape velocity from the earth is
1
1
k
m
s
−
1
, the escape velocity from the surface ofthe planet would be
A
1
1
0
k
m
s
−
1
B
0
.
1
1
k
m
s
−
1
C
1
.
1
k
m
s
−
1
D
1
1
k
m
s
−
1
Hard
JEE Mains
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>
At what distance above the surface of earth, the gravitational force will be reduced by
1
0
%
, if the radius of earth is
6
3
7
0
Km.
A
7
5
0
K
m
B
6
5
0
K
m
C
4
5
0
K
m
D
3
4
4
K
m
Hard
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>
The value of
g
at a height
h
above the surface of the earth is the same as at a depth
d
below the surface of the earth. When both
d
and
h
are much smaller than the radius of earth, then which one of the following is correct
A
d
=
2
h
B
d
=
2
3
h
C
.
d
=
2
h
D
d
=
h
Hard
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>
A boy can jump to a height
h
from ground on earth . What should be the radius of a sphere of density
δ
such that on jumping on it, he escapes out of the gravitational field of the sphere?
A
3
g
h
4
π
G
δ
B
3
G
δ
4
π
g
h
C
4
π
G
δ
3
g
h
D
4
π
g
h
3
G
δ
Hard
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>
A particle of mass 1kg is placed at a distance of 4m from the centre and on the axis of a uniform ring of mass 5kg and radius 3m. The work done to increase the distance of the particle from 4m to
3
m
is.
A
3
G
J
B
4
G
J
C
5
G
J
D
6
G
J
Hard
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>
A particle of mass
1
0
g
m
is kept on the surface of a uniform sphere of mass
1
0
0
k
g
and radius
1
0
c
m
. Find the work done against the gravitational force between them, to take the particle far away from the sphere.
(
G
=
6
.
6
7
×
1
0
−
1
1
N
m
2
/
K
g
2
)
A
3
.
3
3
×
1
0
−
9
J
B
3
.
3
3
×
1
0
−
1
0
J
C
6
.
6
7
×
1
0
−
9
J
D
6
.
6
7
×
1
0
−
1
0
J
Hard
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>
The work done in shifting a particle of mass
m
from the centre of earth to the surface of the earth is
A
−
m
g
R
B
2
1
m
g
R
C
z
e
r
o
D
m
g
R
Hard
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>
The work done by an external agent to shift a point mass from infinity to the centre of the earth is W. Then choose the correct relation.
A
W
=
0
B
W > 0
C
W < 0
D
W
≤
0
Hard
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>
If g is the acceleration due to gravity on the earth's surface, the gain in the potential energy of an object of mass m raised from the surface of the earth to a height equal to the radius R of the earth, is:
A
2
m
g
R
B
2
1
m
g
R
C
4
1
m
g
R
D
m
g
R
Hard
JEE Mains
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>
A particle hanging from a massless spring stretches it by 2 cm at earths surface. How much will the same particle stretch the spring at a height of 2624 km from the surface of the earth? (Radius of earth
=
6400 km).
A
1
c
m
B
2
c
m
C
3
.
3
c
m
D
4
c
m
Hard
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>