(i to 2m/s Motor
ILATIVE coul
2m/s
Va VB(a 3m/s
=
=
Via =
-Fe
=
3 -
2 =
(m/s
Val
>
-
Vaya -
vole
= 2 -
3 =
-
Im/s -
i O B
2m/s
- ↓
Val = -
2 ( 3) =
=
= 5m/s
↑ 2 m/s = 2j
ii
=
-21
O
-
VA
M
2u &
Fa
=
-
= 25 - 25
= + 22 =
2v2 m/s
i)
N
55
taken
I
N .
5 m/s Total time =
sysum
W E
S
"a 4(5 5)
=
-
Hawt =
NEED =
22m/5
Note that Tav =
j- N
along N-W
·
direction
S
RAIN-MAN PROBLEMS :
-
Ve
= vertically downwards
-
Vr/e caropy
.
o of has to be
·
N
umbrella
-
111/1/1 held far to this
direction
#
:
Cae2
- Vi
tanc
=
= tant
(
is west rel-3 km/h and
eg
-
: A man
walking due
rentically
with
Find the
wel 4km/hr
&
to be with
rau
appears falling n
= ·
writ ground
velocity of rain
3 km/h =T
Vaye
=
Vem = 4km/h
- >
V/M = + (-
)
Vale =? N
SinD =
35
· -m =
3
4/5
·
20 =
3
Extra
:
3 A Banda situated at the vertis of
- particles ,
an
equilatual DABC of side'd'at
t = o . Each
particle
has its velocity
moves with a constant speed v .
A
always
At what
along AB
,
B
along
BC and
Calong CA .
time will
mee each other .
t h ey
A
=>
Va , 60
along AB :
/b) along A = - Fialong AB .
-
v (vago) -
"
=> V +V , 60
= 3V
Z
time taken
List -
>
-
MogA
v
X
d
=For a
=
=
v
v
-
-
(o)
dist
time
taken
Fr
F
- [A/1) along AB
=
FA-EBalong As
60 D
= v -
va , 60
A V B = v -
V
<
& =
-
Einekhen=
dist
·.
VER-BOATYPERSON PROBLE .
S#
-
>
l >
- V
actual mote in
will take
-
place
along Vs/p
>
-
TR
>
-
U V
-
5/1
= + ()
& time faken
by swimmer to cres the ri
t =
-dist- -
speed far
to river flow (speed) y
t-
-
i Drift when the swimmer reaches the opposite
Bank .
Drift =
Speed) ,
time
↑
(R- Vssino)
=
.
t
Drift (Vr-Virtio)
=
u
Vs/r los O
Di Minimum
possible Eie to wier :
the
cross
o
t =
If t is min => 200 = max
,
30 = 1
0 =
00
trin
=
=>
i t DRIFT :
-Vardinato
=
·
Vr =
Vs/psin O
0 =
sint)
To at rate of 3
hm/h , the vai
Extra
-
:
a man
walking
to When he increases his
appears fall vertically .
speed
to 6hm/h ,
it
appears
to meet him at
angle of 450 with
vertical .
Find speed of .
rain
S ↓
-
=
355-
-
V = a4 + by
-
F
a + by 6
a
-
=
Vr = 62 +
=
(a -
6)i + bj
T
=
-
vertical b
VR/M Gr 45 = a 6
-
+
=
-
=
=> 3 -
6 =
b
X-cmpisse =
G-3) i th b -
=
3
I
a -
3 =
0
a =
= 3
2i
-
V =
-
3j
v =+
)
distance between in 4m
eg : A motorboat covers a
2
pts ,
to the In hour much
along the flow and Sh
opp .
flow
time this distance can be covered in still water
.
↓
Au :
(th) & -) =
Let
a - d >
-
-
B
A &
>
- VB
>
-
VR
ist
t
=
=
4
-
A B
>
-
VR
--
Vi
=
8
R
Ex : A man can surim at
speed of 5km/h in still water
.
>
-
at
He wants toarows as 1600m wide river flowing
4km/h .
He
keeps himself at an
angle of 127 with
the river flows while
siming
i) Find time taken to wors the view (24mi)
ii) distance travelled by him along the floor (400 .
m
VsIr Stuffer
=
Vr 4 km/hr
S=
=
1600m
(t spe
=
= 5
= 0 .
4h
=
0 .
4X60
= 24 ni
dist along flow-drift -Vsdin3to) t
()
= .
(
-
5.
) (0.)
=
1 (0 .
4) kn
=
m
