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Prerna Varshney
Subject: Physics
, asked on 30/4/18
Please give PROPER REASON of each step for your solution with SUITABLE FIGURE.
Q.35. The circular motion of a particle with constant speed is
(a) simple harmonic but not periodic
(b) periodic and simple harmonic
(c) neither periodic nor simple harmonic
(d) periodic but not simple harmonic
Answer
2
Prerna Varshney
Subject: Physics
, asked on 30/4/18
please give proper reason for each step of your solution with a suitable figure for better understand plssssss
31. A heavy stone hanging from a massless string of length 15 m is projected horizontally with speed 147 ms
-1
. The speed of the particle at the point where the tension in the string equals the weight of the particle is
(a) 10 ms
-1
(b) 7 ms
-1
(c) 12 ms
-1
(d) None of these
Answer
2
Prerna Varshney
Subject: Physics
, asked on 30/4/18
Give reason of each step of your solution:
38. A stone is tied to a string a length l and its whirled in a vertical circle with the other end of the string as the centre. At a certain instant of time, the stone is at its lowest position and has a speed u. The magnitude of the change in velocity as it reaches a position where the string in horizontal (g being acceleration due to gravity ) is.
a
2
u
2
-
g
l
b
u
2
-
g
l
c
u
-
u
2
-
2
g
l
d
2
g
l
Answer
1
Prerna Varshney
Subject: Physics
, asked on 30/4/18
Give proper reason of each step of your solution:
39. A hemispherical below of radius R is rotating about its axis of symmetry which is kept vertical. A small ball kept in the bowl rotates with the bowl without slipping on its surface. If the surface of the bowl is smooth and the angle made by the radius through the ball with the vertical is
α
. Find the angular speed at which of bowl is rotating.
a
g
R
sin
α
b
g
R
cos
α
c
g
1
R
cos
α
d
g
1
R
sin
α
Answer
1
Prerna Varshney
Subject: Physics
, asked on 30/4/18
Give proper reason of each step of your answer
Q.31. A heavy stone hanging from a massless string of length 15 m is projected horizontally with speed 147 m
s
-
1
. The speed of the particle at the point where the tension in the string equals the weight of the particle is
(a) 10 m
s
-
1
(b) 7 m
s
-
1
(c) 12 m
s
-
1
(d) None of these
Answer
1
Prerna Varshney
Subject: Physics
, asked on 30/4/18
Give reason to not to choose option a,b & d and to choose option c:
33. A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle. The motion of the particle takes in a plane. It follows that.
(a) its velocity is constant
(b) its acceleration is constant
(c) its kinetic energy is constant
(d) it does not move on a circular path.
Answer
1
Ranjitha R
Subject: Physics
, asked on 29/4/18
a spring const of force k is cut into lengths of ratio 1:2:3. they are connected in series and new force constant is k'. then they are connected in parallel and force constant is k''.then k':k''is
1:11
1:6
1:9
1:14
Answer
1
Prerna Varshney
Subject: Physics
, asked on 27/4/18
Q. A piece of marble is projectile from the earth's surface with velocity of 50 ms
-1
. 2 s later it just clears wall 5 m high . What is the angle of projection ? (a)
45
°
(
b
)
30
°
(
c
)
60
°
(
d
)
n
o
n
e
o
f
t
h
e
s
e
Answer
1
Prerna Varshney
Subject: Physics
, asked on 27/4/18
Q.1 The displacement of a particle moving in a straight line is described by the relation s = 6+12 t-2 t
2
, here ,x is in meter and t in second . The distance covered by particle in first 5 s is (a) 20 m (b) 32 m (c) 24 m (d) 26 m
Answer
1
Dharunika Vijayakumar
Subject: Physics
, asked on 25/4/18
a 100 w bulb is designed to operate on a potential difference of 230 V
i) find the resistance of the bulb
ii) find the current drawn by it if its bulb operated at a potential difference for which it is designed .
Answer
1
Aparna Sahu
Subject: Physics
, asked on 25/4/18
Solve this:
Q. The radiant energy from the sun, incident normally at the surface of earth, is 20 kcal/
m
2
min. What would have been the radiant energy incident normally on the earth, if the sun had a temperature twice of the present one ?
(a) 160 kcal/(
m
2
-min)
(b) 40 kcal/(
m
2
-min)
(c) 320 kcal/(
m
2
-min)
(d) 80 kcal/(
m
2
-min).
Answer
1
Aparna Sahu
Subject: Physics
, asked on 24/4/18
Solve this:
Q.23. In the figure below, the capacitance of each capacitor is 3
μ
The effective capacitance between A and B is
(a)
3
4
μ
F
(b) - 3
μ
F
(c) 6
μ
F
(d) 5
μ
F
Answer
2
Aparna Sahu
Subject: Physics
, asked on 24/4/18
Solve this:
4. Two temperature scales A and B are related by
A
-
42
110
=
B
-
72
220
. At which temperature two scales have the same reading ?
(a) -42
o
(b) 42
o
(c) 12
o
(d) -40
o
Answer
1
Aparna Sahu
Subject: Physics
, asked on 23/4/18
Solve this:
Q.19. Five equal resistances, each of resistance R, are connected as shown in figure below. A battery of V volt is connected between A and B. The current flowing in FC will be
(a) 3V/R
(b) V/R
(c) V/2R
(d) 2V/R
Answer
1
Aparna Sahu
Subject: Physics
, asked on 23/4/18
Solve this:
11
.
A
n
i
r
o
n
r
o
d
o
f
l
e
n
g
t
h
100
c
m
a
n
d
10
c
m
2
c
r
o
s
s
-
s
e
c
t
i
o
n
i
s
h
e
a
t
e
d
f
r
o
m
0
°
C
t
o
100
°
.
I
f
i
t
i
s
n
o
t
a
l
l
o
w
e
d
t
o
b
e
n
d
o
r
e
x
p
a
n
d
,
w
h
a
t
f
o
r
c
e
i
s
d
e
v
e
l
o
p
e
d
i
n
i
t
?
G
i
v
e
n
t
h
a
t
Y
-
10
12
d
y
n
e
/
c
m
2
a
n
d
α
=
10
-
5
/
°
C
(
a
)
10
8
d
y
n
e
(
b
)
10
9
d
y
n
e
(
c
)
10
10
d
y
n
e
(
d
)
10
11
d
y
n
e
Answer
1
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What are you looking for?
Q.35. The circular motion of a particle with constant speed is
(a) simple harmonic but not periodic
(b) periodic and simple harmonic
(c) neither periodic nor simple harmonic
(d) periodic but not simple harmonic
31. A heavy stone hanging from a massless string of length 15 m is projected horizontally with speed 147 ms-1. The speed of the particle at the point where the tension in the string equals the weight of the particle is
(a) 10 ms-1 (b) 7 ms-1
(c) 12 ms-1 (d) None of these
38. A stone is tied to a string a length l and its whirled in a vertical circle with the other end of the string as the centre. At a certain instant of time, the stone is at its lowest position and has a speed u. The magnitude of the change in velocity as it reaches a position where the string in horizontal (g being acceleration due to gravity ) is.
39. A hemispherical below of radius R is rotating about its axis of symmetry which is kept vertical. A small ball kept in the bowl rotates with the bowl without slipping on its surface. If the surface of the bowl is smooth and the angle made by the radius through the ball with the vertical is . Find the angular speed at which of bowl is rotating.
Q.31. A heavy stone hanging from a massless string of length 15 m is projected horizontally with speed 147 m . The speed of the particle at the point where the tension in the string equals the weight of the particle is
(a) 10 m
(b) 7 m
(c) 12 m
(d) None of these
33. A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle. The motion of the particle takes in a plane. It follows that.
(a) its velocity is constant
(b) its acceleration is constant
(c) its kinetic energy is constant
(d) it does not move on a circular path.
1:11
1:6
1:9
1:14
i) find the resistance of the bulb
ii) find the current drawn by it if its bulb operated at a potential difference for which it is designed .
Q. The radiant energy from the sun, incident normally at the surface of earth, is 20 kcal/ min. What would have been the radiant energy incident normally on the earth, if the sun had a temperature twice of the present one ?
(a) 160 kcal/(-min)
(b) 40 kcal/(-min)
(c) 320 kcal/(-min)
(d) 80 kcal/(-min).
Q.23. In the figure below, the capacitance of each capacitor is 3 The effective capacitance between A and B is
(a) F
(b) - 3 F
(c) 6 F
(d) 5 F
4. Two temperature scales A and B are related by . At which temperature two scales have the same reading ?
(a) -42o
(b) 42o
(c) 12o
(d) -40o
Q.19. Five equal resistances, each of resistance R, are connected as shown in figure below. A battery of V volt is connected between A and B. The current flowing in FC will be
(a) 3V/R
(b) V/R
(c) V/2R
(d) 2V/R