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Surbhi Singh
Subject: Physics
, asked on 14/5/18
Please give a detailed solution
Q.
A disc of mass m and radius r is free to rotate about its centre as shown in the figure. A string is wrapped over its rim and a block of mass m is attached to free end of the string. The system is released from rest. The speed of the block as it descends though a height h, is
Answer
1
Surbhi Singh
Subject: Physics
, asked on 14/5/18
pls answer this wirh a detailed solution:
18.
A thin wire Of length l and mass m is bent in the form of a semicircle as shown. Its moment of inertia about an axis joining its free ends will be
1
ml
2
2
Zero
3
ml
2
π
2
4
ml
2
2
π
2
Answer
1
Surbhi Singh
Subject: Physics
, asked on 14/5/18
four thin uniform rods each of length L and mass m are joined to form of a square . the moment of inertia of the square about an axis along its one diagonal is
Answer
1
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
Explain qno.10 Ans(2)
Q.10. A force F is applied on a hollow sphere of mass M and radius R at a distance
R
3
from its centre of mass as shown in figure. If surface is rough then what will be the direction of rolling friction?
(1) Forward
(2) Backward
(3) First Forward then backward
(4) Rolling friction will not set
Answer
1
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
8) A ring of mass M and radius R is rolling without slipping with angular velocity
ω
on the horizontal plane as shown the figure. The magnitude al angular momentum of ring about the point of the contact of the ring. (Answer 2)
(
1
)
M
R
2
ω
(
2
)
2
M
R
2
ω
(
3
)
1
2
M
R
2
ω
(
4
)
Z
e
r
o
Answer
1
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
Explain qno.7 Ans(1)
Answer
0
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
6) A circular object of mass m and radius R is rolling without slipping on a floor as shown in figure, such that velocity of its centre of mass is V
0
. What will be the velocity of point P at this instant? (Answer 3)
(
1
)
V
0
(
2
)
2
V
0
(
3
)
2
V
0
(
4
)
3
V
0
Answer
1
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
Q. A disc of radius R and mass M have only translational motion. Initial velocity of its centre of mass is
V
0
and then gently place on a rough horizontal surface. The coefficient of friction between surface and disc is
μ
. Angular velocity about its centre of mass when it start pure rolling is
2
V
0
/R
2
V
0
/3R
3
V
0
/2R
V
0
/R
Answer
1
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
Explain qno.2 .Ans(3):
2. Three identical rods each of mass
m
and length
l
form an equilateral triangle. Moment of inertia of the system about an axis as shown in figure will be.
1
3
ml
2
2
2
ml
2
2
3
ml
2
4
4
2
3
ml
2
Answer
1
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
Explain qno.41. Ans(1)
Answer
0
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
Explain qno.35.
Q.35. A disc is in the condition of pure rolling on the horizontal surface. The velocity of centre of mass is
v
0
. If radius of disc is R, then the speed of point P is
O
P
=
R
3
Answer
0
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
Explain qno.28. Ans(2):
28. A disc of mass m and radius r is placed on a rough horizontal surface. A cue of mass m hits the disc at a height h from the axis passing through centre and parallel to the surface. The cue stops and falls down after impact. The disc starts pure rolling for.
1
h
<
r
3
2
h
=
r
2
3
h
>
r
2
4
h
≥
r
2
Answer
0
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
Explain qno.19. Ans(1):
19. A particle of mass 2 kg is moving along line 'AB' according to y= x-4 with speed 4 m/s, then angular momentum about 'O' is .
1
16
2
kg
m
2
/
s
2
32
2
kg
m
2
/
s
3
32
kg
m
2
/
s
4
16
kg
m
2
/
s
Answer
0
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
Explain qno.17. Ans(3):
17. A ring of mass 'm' (free to rotate about its centre c) is wrapped by a thread which does not slip on the ring. If the thread is pulled with an acceleration 'a' then the tension in the string is.
1
ma
2
Zero
3
ma
2
4
ma
3
Answer
0
Jeneeta Eliza John
Subject: Physics
, asked on 2/5/18
Explain qno.3 Ans(2)
Answer
0
1
2
3
4
5
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Q. A disc of mass m and radius r is free to rotate about its centre as shown in the figure. A string is wrapped over its rim and a block of mass m is attached to free end of the string. The system is released from rest. The speed of the block as it descends though a height h, is
18. A thin wire Of length l and mass m is bent in the form of a semicircle as shown. Its moment of inertia about an axis joining its free ends will be
Q.10. A force F is applied on a hollow sphere of mass M and radius R at a distance from its centre of mass as shown in figure. If surface is rough then what will be the direction of rolling friction?
(1) Forward
(2) Backward
(3) First Forward then backward
(4) Rolling friction will not set
Q. A disc of radius R and mass M have only translational motion. Initial velocity of its centre of mass is and then gently place on a rough horizontal surface. The coefficient of friction between surface and disc is . Angular velocity about its centre of mass when it start pure rolling is
2. Three identical rods each of mass m and length l form an equilateral triangle. Moment of inertia of the system about an axis as shown in figure will be.
Q.35. A disc is in the condition of pure rolling on the horizontal surface. The velocity of centre of mass is . If radius of disc is R, then the speed of point P is
28. A disc of mass m and radius r is placed on a rough horizontal surface. A cue of mass m hits the disc at a height h from the axis passing through centre and parallel to the surface. The cue stops and falls down after impact. The disc starts pure rolling for.
19. A particle of mass 2 kg is moving along line 'AB' according to y= x-4 with speed 4 m/s, then angular momentum about 'O' is .
17. A ring of mass 'm' (free to rotate about its centre c) is wrapped by a thread which does not slip on the ring. If the thread is pulled with an acceleration 'a' then the tension in the string is.