Motion in a Plane- 3 Practice Questions - DPP for NEET

 Page 1


DIRECTIONS (Q.1-Q.19) : There are 19 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 A man whirls a stone round his head on the end of a string
4.0 metre long. Can the string be in a horizontal, plane? If
the stone has a mass of 0.4 kg and the string will break, if
the tension in it exceeds 8 N. The smallest angle the string
can make with the horizontal and the speed of the stone
will respectively be  (Take g = 10 m/sec
2
)
(a) 30º, 7.7 m/s (b) 60º, 7.7 m/s
(c) 45º, 8.2 m/s (d) 60º, 8.7 m/s
Q.2 In figure ABCDE is a channel in the vertical plane, part BCDE
being circular with radius r.  A ball is released from A and
slides without friction and without rolling. It will complete
the loop path when
A
E
D
C
B
r
r
r
(a) h > 5 r/2 (b) h < 5 r/2
(c) h < 2r/5 (d) h > 2r/5
Q.3 An aircraft loops the loop of radius R = 500 m with a
constant velocity v = 360 km/h. The weight of the flyer of
mass m = 70 kg in the lower, upper and middle points of
the loop will respectively be-
(a) 210 N, 700 N, 1400 N (b) 1400 N, 700 N, 2100 N
(c) 700 N, 1400 N, 210 N (d) 2100 N, 700 N, 1400 N
Page 2


DIRECTIONS (Q.1-Q.19) : There are 19 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 A man whirls a stone round his head on the end of a string
4.0 metre long. Can the string be in a horizontal, plane? If
the stone has a mass of 0.4 kg and the string will break, if
the tension in it exceeds 8 N. The smallest angle the string
can make with the horizontal and the speed of the stone
will respectively be  (Take g = 10 m/sec
2
)
(a) 30º, 7.7 m/s (b) 60º, 7.7 m/s
(c) 45º, 8.2 m/s (d) 60º, 8.7 m/s
Q.2 In figure ABCDE is a channel in the vertical plane, part BCDE
being circular with radius r.  A ball is released from A and
slides without friction and without rolling. It will complete
the loop path when
A
E
D
C
B
r
r
r
(a) h > 5 r/2 (b) h < 5 r/2
(c) h < 2r/5 (d) h > 2r/5
Q.3 An aircraft loops the loop of radius R = 500 m with a
constant velocity v = 360 km/h. The weight of the flyer of
mass m = 70 kg in the lower, upper and middle points of
the loop will respectively be-
(a) 210 N, 700 N, 1400 N (b) 1400 N, 700 N, 2100 N
(c) 700 N, 1400 N, 210 N (d) 2100 N, 700 N, 1400 N
2
DPP/ P 08
Q.4 A particle of mass 3 kg is moving under the action of a
central force whose potential energy is given by U(r) =
10r
3
 joule. For what energy and angular momentum will
the orbit be a circle of radius 10 m ?
(a) 2.5 × 10
4
 J, 3000 kgm
2
/sec
(b) 3.5 × 10
4
 J, 2000 kgm
2
/sec
(c) 2.5 × 10
3
 J, 300 kgm
2
/sec
(d) 3.5 × 10
3
 J, 300 kgm
2
/sec
Q.5 A string of length 1 m is fixed at one end and carries a
mass of 100 gm at the other end. The string makes 2/ p
revolutions per second about a vertical axis through the
fixed end. The angle of inclination of the string with the
vertical, and the linear velocity of the mass will respec-
tively be -  (in M.K.S. system)
(a) 52º14', 3.16 (b) 50º14', 1.6
(c) 52º14', 1.6 (d) 50º14', 3.16
Q.6 A particle of mass m is moving in a circular path of constant
radius r such that its centripetal acceleration a
c
 is varying
with time t as a
c
 = k
2
rt
2
, where k is a constant. The power
delivered to the particle by the force acting on it will be -
(a) mk
2
t
2
r (b) mk
2
r
2
t
2
(c)m
2
k
2
t
2
r
2
(d) mk
2
r
2
t
Q.7 A car is moving in a circular path of radius 100 m with
velocity of 200 m/sec such that in each sec its velocity
increases by 100 m/s, the net acceleration of car will be -
(in m/sec)
(a) 100
17
(b) 10
7
(c) 10
3
(d) 100
3
Q.8 A 4 kg balls is swing in a vertical circle at the end of a cord
1 m long. The maximum speed at which it can swing if the
cord can sustain maximum tension of 163.6 N will be -
(a) 6 m/s (b) 36 m/s (c) 8 m/s (d) 64 m/s
Q.9 The string of a pendulum is horizontal. The mass of the
bob is m. Now the string is released. The tension in the
string in the lowest position is -
(a) 1 mg (b) 2 mg (c) 3 mg (d) 4 mg
Q.10 A swimmer can swim in still water at a rate 4 km/h. If he
swims in a river flowing at 3 km/h and keeps his direction
(w .r.t. water) perpendicular to the current. Find his velocity
w .r.t. the ground.
(a) 3 km/hr (b) 5 km/hr
(c) 4 km/hr (d) 7 km/hr
Q.11 The roadway bridge over a canal is the form of an arc of a
circle of radius 20 m. What is the minimum speed with
which a car can cross the bridge without leaving contact
with the ground at the highest point (g = 9.8 m/s
2
)
(a) 7 m/s (b) 14 m/s (c) 289 m/s (d) 5 m/s
Q.12 A cane filled with water is revolved in a vertical circle of
radius 0.5 m and the water does not fall down. The
maximum period of revolution must be -
(a) 1.45 (b) 2.45 (c) 14.15 (d) 4.25
Q.13 A particle of mass m slides down from the vertex of semi-
hemisphere, without any initial velocity. At what height
from horizontal will the particle leave the sphere-
(a)
2
3
R (b)
3
2
R (c)
5
8
R (d)
8
5
R
Q.14 A body of mass m tied at the end of a string of length l is
projected with velocity 4g l , at what height will it leave
the circular path -
(a)
5
3
l (b)
3
5
l (c)
1
3
l (d)
2
3
l
Q.15 A string of length L is fixed at one end and carries a mass
M at the other end. The string makes 2/ p revolutions per
second around the vertical axis through the fixed end as
shown in the figure, then tension in the string is
(a) ML
(b) 2 ML
L
R
S
T
M
q
(c) 4 ML
(d) 16 ML
Q.16 A train has to negotiate a curve of radius  400 m. By how
much should the outer rail be raised with respect to inner
rail for a speed of 48 km/hr. The distance between the rails
is 1 m.
(a) 12 m (b) 12 cm
(c) 4.5 cm (d) 4.5 m
Page 3


DIRECTIONS (Q.1-Q.19) : There are 19 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 A man whirls a stone round his head on the end of a string
4.0 metre long. Can the string be in a horizontal, plane? If
the stone has a mass of 0.4 kg and the string will break, if
the tension in it exceeds 8 N. The smallest angle the string
can make with the horizontal and the speed of the stone
will respectively be  (Take g = 10 m/sec
2
)
(a) 30º, 7.7 m/s (b) 60º, 7.7 m/s
(c) 45º, 8.2 m/s (d) 60º, 8.7 m/s
Q.2 In figure ABCDE is a channel in the vertical plane, part BCDE
being circular with radius r.  A ball is released from A and
slides without friction and without rolling. It will complete
the loop path when
A
E
D
C
B
r
r
r
(a) h > 5 r/2 (b) h < 5 r/2
(c) h < 2r/5 (d) h > 2r/5
Q.3 An aircraft loops the loop of radius R = 500 m with a
constant velocity v = 360 km/h. The weight of the flyer of
mass m = 70 kg in the lower, upper and middle points of
the loop will respectively be-
(a) 210 N, 700 N, 1400 N (b) 1400 N, 700 N, 2100 N
(c) 700 N, 1400 N, 210 N (d) 2100 N, 700 N, 1400 N
2
DPP/ P 08
Q.4 A particle of mass 3 kg is moving under the action of a
central force whose potential energy is given by U(r) =
10r
3
 joule. For what energy and angular momentum will
the orbit be a circle of radius 10 m ?
(a) 2.5 × 10
4
 J, 3000 kgm
2
/sec
(b) 3.5 × 10
4
 J, 2000 kgm
2
/sec
(c) 2.5 × 10
3
 J, 300 kgm
2
/sec
(d) 3.5 × 10
3
 J, 300 kgm
2
/sec
Q.5 A string of length 1 m is fixed at one end and carries a
mass of 100 gm at the other end. The string makes 2/ p
revolutions per second about a vertical axis through the
fixed end. The angle of inclination of the string with the
vertical, and the linear velocity of the mass will respec-
tively be -  (in M.K.S. system)
(a) 52º14', 3.16 (b) 50º14', 1.6
(c) 52º14', 1.6 (d) 50º14', 3.16
Q.6 A particle of mass m is moving in a circular path of constant
radius r such that its centripetal acceleration a
c
 is varying
with time t as a
c
 = k
2
rt
2
, where k is a constant. The power
delivered to the particle by the force acting on it will be -
(a) mk
2
t
2
r (b) mk
2
r
2
t
2
(c)m
2
k
2
t
2
r
2
(d) mk
2
r
2
t
Q.7 A car is moving in a circular path of radius 100 m with
velocity of 200 m/sec such that in each sec its velocity
increases by 100 m/s, the net acceleration of car will be -
(in m/sec)
(a) 100
17
(b) 10
7
(c) 10
3
(d) 100
3
Q.8 A 4 kg balls is swing in a vertical circle at the end of a cord
1 m long. The maximum speed at which it can swing if the
cord can sustain maximum tension of 163.6 N will be -
(a) 6 m/s (b) 36 m/s (c) 8 m/s (d) 64 m/s
Q.9 The string of a pendulum is horizontal. The mass of the
bob is m. Now the string is released. The tension in the
string in the lowest position is -
(a) 1 mg (b) 2 mg (c) 3 mg (d) 4 mg
Q.10 A swimmer can swim in still water at a rate 4 km/h. If he
swims in a river flowing at 3 km/h and keeps his direction
(w .r.t. water) perpendicular to the current. Find his velocity
w .r.t. the ground.
(a) 3 km/hr (b) 5 km/hr
(c) 4 km/hr (d) 7 km/hr
Q.11 The roadway bridge over a canal is the form of an arc of a
circle of radius 20 m. What is the minimum speed with
which a car can cross the bridge without leaving contact
with the ground at the highest point (g = 9.8 m/s
2
)
(a) 7 m/s (b) 14 m/s (c) 289 m/s (d) 5 m/s
Q.12 A cane filled with water is revolved in a vertical circle of
radius 0.5 m and the water does not fall down. The
maximum period of revolution must be -
(a) 1.45 (b) 2.45 (c) 14.15 (d) 4.25
Q.13 A particle of mass m slides down from the vertex of semi-
hemisphere, without any initial velocity. At what height
from horizontal will the particle leave the sphere-
(a)
2
3
R (b)
3
2
R (c)
5
8
R (d)
8
5
R
Q.14 A body of mass m tied at the end of a string of length l is
projected with velocity 4g l , at what height will it leave
the circular path -
(a)
5
3
l (b)
3
5
l (c)
1
3
l (d)
2
3
l
Q.15 A string of length L is fixed at one end and carries a mass
M at the other end. The string makes 2/ p revolutions per
second around the vertical axis through the fixed end as
shown in the figure, then tension in the string is
(a) ML
(b) 2 ML
L
R
S
T
M
q
(c) 4 ML
(d) 16 ML
Q.16 A train has to negotiate a curve of radius  400 m. By how
much should the outer rail be raised with respect to inner
rail for a speed of 48 km/hr. The distance between the rails
is 1 m.
(a) 12 m (b) 12 cm
(c) 4.5 cm (d) 4.5 m
DPP/ P 08
3
Q.21 A swimmer who can  swim in a river with speed mv (with
respect to still water) where v is the velocity of river
current, jumps into the river from one bank to cross the
river. Then
(1) If m < 1 he cannot cross the river
(2) If m £ 1 he cannot reach a point on other bank di-
rectly opposite to his starting point.
(3) If m > 1 he can reach a point on other bank
(4) He can reach the other bank at some point, whatever
be the value of m.
Q.22 Consider two children riding on the merry-go-round Child
1 sits near the edge, Child 2 sits closer to the centre.
Let v
l
 and v
2
 denote the linear speed of child 1 and child 2,
respectively. Which of the following is/are wrong ?
(1) We cannot determine v
1
 & v
2
 without more
information
(2) v
1
 = v
2
(3) v
1
 < v
2
(4) v
1
 > v
2
DIRECTIONS (Q.23-Q.25) : Read the passage given below
and answer the questions that follows :
Three of the fundamental constants of physics are the universal
gravitational constant, G = 6.7 × 10
–11
m
3
kg
–1
s
–2
, the speed  of
light, c = 3.0 × 10
8
 m/s, and Planck’s constant, h = 6.6 × 10
–34
 Js
–1
.
Two particles A and B are projected in the vertical plane with
same initial velocity u
0
 from part (0, 0) and ( l, –h) towards each
other as shown in figure at t = 0.
x
y
A
B
(0,0)
u
0
u
0
g = 10m/s
2
h
( , –h) l
l
Q.17 A ship is steaming towards east at a speed of 12 ms
–1
.  A
woman runs across the deck at a speed of 5 ms
–1
 in the
direction at right angles to the direction of motion of the
ship i.e. towards north.  What is the velocity of the woman
relative to sea ?
(a) 13 m/s (b) 5 m/s (c) 12 m/s (d) 17 m/s
Q.18A man is walking on a level road at a speed of 3 km/h.
Raindrops fall vertically with a speed of 4 km/h. Find the
velocity of raindrops with respect to the men.
(a) 3 km/hr (b) 4 km/hr (c) 5 km/hr (d) 7 km/hr
Q.19 A stone of mass 1 kg tied to a light inextensible string of
le ngth 
10
Lm
3
=
 is whirling in a circular path of radius L
in a vertical plane. If the ratio of the maximum tension in
the string to the minimum tension in the string is 4 and if g
is taken to be 10m / sec
2
, the speed of the stone at the
highest point of the circle is
(a) 20 m/sec (b) 
10 3m/sec
(c)
5 2m/sec
(d) 10 m/sec
DIRECTIONS (Q.20-Q.22) : In the following questions,
more than one of the answers  given are correct. Select the
correct answers and mark it according to the following
codes:
Codes :
(a) 1, 2 and 3 are correct (b) 1 and 2 are correct
(c) 2 and 4 are correct (d) 1 and 3 are correct
Q.20 Two bodies P and Q are moving along positive x-axis their
position-time graph is shown below. If 
PQ
V
r
 is velocity of
P w.r.t. Q and 
QP
V
r
 is velocity of Q w.r.t P , then
(1)
PQ QP
|V| |V| =
rr
 = constant
(2)
PQ
V
r
 towards origin
(3)
QP
V
r
 towards origin
P
Q
t
x
(4)
PQ QP
|V| |V| ¹
rr
 = constant
Page 4


DIRECTIONS (Q.1-Q.19) : There are 19 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 A man whirls a stone round his head on the end of a string
4.0 metre long. Can the string be in a horizontal, plane? If
the stone has a mass of 0.4 kg and the string will break, if
the tension in it exceeds 8 N. The smallest angle the string
can make with the horizontal and the speed of the stone
will respectively be  (Take g = 10 m/sec
2
)
(a) 30º, 7.7 m/s (b) 60º, 7.7 m/s
(c) 45º, 8.2 m/s (d) 60º, 8.7 m/s
Q.2 In figure ABCDE is a channel in the vertical plane, part BCDE
being circular with radius r.  A ball is released from A and
slides without friction and without rolling. It will complete
the loop path when
A
E
D
C
B
r
r
r
(a) h > 5 r/2 (b) h < 5 r/2
(c) h < 2r/5 (d) h > 2r/5
Q.3 An aircraft loops the loop of radius R = 500 m with a
constant velocity v = 360 km/h. The weight of the flyer of
mass m = 70 kg in the lower, upper and middle points of
the loop will respectively be-
(a) 210 N, 700 N, 1400 N (b) 1400 N, 700 N, 2100 N
(c) 700 N, 1400 N, 210 N (d) 2100 N, 700 N, 1400 N
2
DPP/ P 08
Q.4 A particle of mass 3 kg is moving under the action of a
central force whose potential energy is given by U(r) =
10r
3
 joule. For what energy and angular momentum will
the orbit be a circle of radius 10 m ?
(a) 2.5 × 10
4
 J, 3000 kgm
2
/sec
(b) 3.5 × 10
4
 J, 2000 kgm
2
/sec
(c) 2.5 × 10
3
 J, 300 kgm
2
/sec
(d) 3.5 × 10
3
 J, 300 kgm
2
/sec
Q.5 A string of length 1 m is fixed at one end and carries a
mass of 100 gm at the other end. The string makes 2/ p
revolutions per second about a vertical axis through the
fixed end. The angle of inclination of the string with the
vertical, and the linear velocity of the mass will respec-
tively be -  (in M.K.S. system)
(a) 52º14', 3.16 (b) 50º14', 1.6
(c) 52º14', 1.6 (d) 50º14', 3.16
Q.6 A particle of mass m is moving in a circular path of constant
radius r such that its centripetal acceleration a
c
 is varying
with time t as a
c
 = k
2
rt
2
, where k is a constant. The power
delivered to the particle by the force acting on it will be -
(a) mk
2
t
2
r (b) mk
2
r
2
t
2
(c)m
2
k
2
t
2
r
2
(d) mk
2
r
2
t
Q.7 A car is moving in a circular path of radius 100 m with
velocity of 200 m/sec such that in each sec its velocity
increases by 100 m/s, the net acceleration of car will be -
(in m/sec)
(a) 100
17
(b) 10
7
(c) 10
3
(d) 100
3
Q.8 A 4 kg balls is swing in a vertical circle at the end of a cord
1 m long. The maximum speed at which it can swing if the
cord can sustain maximum tension of 163.6 N will be -
(a) 6 m/s (b) 36 m/s (c) 8 m/s (d) 64 m/s
Q.9 The string of a pendulum is horizontal. The mass of the
bob is m. Now the string is released. The tension in the
string in the lowest position is -
(a) 1 mg (b) 2 mg (c) 3 mg (d) 4 mg
Q.10 A swimmer can swim in still water at a rate 4 km/h. If he
swims in a river flowing at 3 km/h and keeps his direction
(w .r.t. water) perpendicular to the current. Find his velocity
w .r.t. the ground.
(a) 3 km/hr (b) 5 km/hr
(c) 4 km/hr (d) 7 km/hr
Q.11 The roadway bridge over a canal is the form of an arc of a
circle of radius 20 m. What is the minimum speed with
which a car can cross the bridge without leaving contact
with the ground at the highest point (g = 9.8 m/s
2
)
(a) 7 m/s (b) 14 m/s (c) 289 m/s (d) 5 m/s
Q.12 A cane filled with water is revolved in a vertical circle of
radius 0.5 m and the water does not fall down. The
maximum period of revolution must be -
(a) 1.45 (b) 2.45 (c) 14.15 (d) 4.25
Q.13 A particle of mass m slides down from the vertex of semi-
hemisphere, without any initial velocity. At what height
from horizontal will the particle leave the sphere-
(a)
2
3
R (b)
3
2
R (c)
5
8
R (d)
8
5
R
Q.14 A body of mass m tied at the end of a string of length l is
projected with velocity 4g l , at what height will it leave
the circular path -
(a)
5
3
l (b)
3
5
l (c)
1
3
l (d)
2
3
l
Q.15 A string of length L is fixed at one end and carries a mass
M at the other end. The string makes 2/ p revolutions per
second around the vertical axis through the fixed end as
shown in the figure, then tension in the string is
(a) ML
(b) 2 ML
L
R
S
T
M
q
(c) 4 ML
(d) 16 ML
Q.16 A train has to negotiate a curve of radius  400 m. By how
much should the outer rail be raised with respect to inner
rail for a speed of 48 km/hr. The distance between the rails
is 1 m.
(a) 12 m (b) 12 cm
(c) 4.5 cm (d) 4.5 m
DPP/ P 08
3
Q.21 A swimmer who can  swim in a river with speed mv (with
respect to still water) where v is the velocity of river
current, jumps into the river from one bank to cross the
river. Then
(1) If m < 1 he cannot cross the river
(2) If m £ 1 he cannot reach a point on other bank di-
rectly opposite to his starting point.
(3) If m > 1 he can reach a point on other bank
(4) He can reach the other bank at some point, whatever
be the value of m.
Q.22 Consider two children riding on the merry-go-round Child
1 sits near the edge, Child 2 sits closer to the centre.
Let v
l
 and v
2
 denote the linear speed of child 1 and child 2,
respectively. Which of the following is/are wrong ?
(1) We cannot determine v
1
 & v
2
 without more
information
(2) v
1
 = v
2
(3) v
1
 < v
2
(4) v
1
 > v
2
DIRECTIONS (Q.23-Q.25) : Read the passage given below
and answer the questions that follows :
Three of the fundamental constants of physics are the universal
gravitational constant, G = 6.7 × 10
–11
m
3
kg
–1
s
–2
, the speed  of
light, c = 3.0 × 10
8
 m/s, and Planck’s constant, h = 6.6 × 10
–34
 Js
–1
.
Two particles A and B are projected in the vertical plane with
same initial velocity u
0
 from part (0, 0) and ( l, –h) towards each
other as shown in figure at t = 0.
x
y
A
B
(0,0)
u
0
u
0
g = 10m/s
2
h
( , –h) l
l
Q.17 A ship is steaming towards east at a speed of 12 ms
–1
.  A
woman runs across the deck at a speed of 5 ms
–1
 in the
direction at right angles to the direction of motion of the
ship i.e. towards north.  What is the velocity of the woman
relative to sea ?
(a) 13 m/s (b) 5 m/s (c) 12 m/s (d) 17 m/s
Q.18A man is walking on a level road at a speed of 3 km/h.
Raindrops fall vertically with a speed of 4 km/h. Find the
velocity of raindrops with respect to the men.
(a) 3 km/hr (b) 4 km/hr (c) 5 km/hr (d) 7 km/hr
Q.19 A stone of mass 1 kg tied to a light inextensible string of
le ngth 
10
Lm
3
=
 is whirling in a circular path of radius L
in a vertical plane. If the ratio of the maximum tension in
the string to the minimum tension in the string is 4 and if g
is taken to be 10m / sec
2
, the speed of the stone at the
highest point of the circle is
(a) 20 m/sec (b) 
10 3m/sec
(c)
5 2m/sec
(d) 10 m/sec
DIRECTIONS (Q.20-Q.22) : In the following questions,
more than one of the answers  given are correct. Select the
correct answers and mark it according to the following
codes:
Codes :
(a) 1, 2 and 3 are correct (b) 1 and 2 are correct
(c) 2 and 4 are correct (d) 1 and 3 are correct
Q.20 Two bodies P and Q are moving along positive x-axis their
position-time graph is shown below. If 
PQ
V
r
 is velocity of
P w.r.t. Q and 
QP
V
r
 is velocity of Q w.r.t P , then
(1)
PQ QP
|V| |V| =
rr
 = constant
(2)
PQ
V
r
 towards origin
(3)
QP
V
r
 towards origin
P
Q
t
x
(4)
PQ QP
|V| |V| ¹
rr
 = constant
4
DPP/ P 08
Q.23 The path of particle A with respect to particle B will be –
(a) parabola
(b) straight line parallel to x-axis
(c) straight line parallel to y-axis
(d) None of these
Q.24 Minimum distance between particle A and B during motion
will be –
(a) l (b)h
(c) 
22
h + l
(d) l + h
Q.25 The time when separation between A and B is minimum is
(a)
0
x
u cos q
(b)
2h
g
(c) 
0
2u cos q
l
(d)
0
2
u cos q
l
DIRECTIONS (Qs. 26-Q.28) : Each of these questions contains
two statements: Statement-1 (Assertion) and Statement-2
(Reason). Each of these questions has four alternative choices,
only one of which is the correct answer. You have to select the
correct choice.
(a) Statement-1 is True, Statement-2 is True; Statement-2 is a
correct explanation for  Statement-1.
(b) Statement-1 is True, Statement-2 is True; Statement-2 is
NOT a correct explanation for Statement-1.
(c) Statement-1 is False, Statement-2 is True.
(d) Statement-1 is True, Statement-2 is False.
Q.26Statement-1  : The relative velocity between any two
bodies moving in opposite direction is equal to sum of the
velocities of two bodies.
Statement-2 : Sometimes relative velocity between two
bodies is equal to difference in velocities of the two.
Q.27 Statement-1: A river is flowing from east to west at a
speed of 5m/min. A man on south bank of river, capable of
swimming 10 m/min in still water, wants to swim across
the river in shortest time. He should swim due north.
Statement-2 : For the shortest time the man needs to swim
perpendicular to the bank.
Q.28 Statement-1 : Rain is falling vertically downwards with
velocity 6 km/h. A man walks with a velocity of 8 km/h.
Relative velocity of rain w.r.t. the man is 10 km/h.
Statement-2 : Relative velocity is the ratio of two
velocities.