Graphics Reference
In-Depth Information
Y
Y
ou
10
v
Y
s
O
v
O
s
Y
y
Q
q
10
Z
25
X
Figure 11.5.
The relative values are
relative location of object:
q
−
y
=
15
i
km
relative velocity of object:
3
j
kmh
−
1
s
O
ˆ
v
O
−
s
Y
ˆ
v
Y
=−
+
4
i
Therefore, from the relative velocity, the relative speed is
5
kmh
−
1
4
2
s
O
ˆ
v
O
−
s
Y
ˆ
v
Y
=
−
+
3
2
=
and the relative direction is
4
5
i
3
5
j
km
v
O
−ˆ
ˆ
v
Y
=−
+
Therefore,
5
j
4
5
i
3
−
−
+
·
15
i
24
kmh
−
1
12
5
=
t
C
=
=
5
Substituting 24 h in Eq. (11.10) gives
5
j
12
5
×
4
5
i
3
d
=
15
i
+
5
×
−
+
5
j
48
5
i
36
d
=
15
i
−
+
5
j
=
27
5
i
36
d
=
+
9
km
Thus, the close encounter occurs 24 hours after the reference time, and the object is 9 km from
you.
