Game Development Reference
InDepth Information
time should be in seconds (s); speed should be in meters per second (m/s); and accel‐
eration should be in meters per second squared (m/s
2
). In the SI system,
g
is 9.8 m/s
2
.
In the second type of problem, the launch point is located on a lower horizontal plane
than the target. In
Figure 62
, the launch point's
y
coordinate is lower than the target's
y
coordinate.
Figure 62. Target higher than launch point
For this type of problem, use the formulas shown in
Table 62
. Notice that most of these
formulas are the same as those shown in
Table 61
.
Table 62. Formulas—target higher than launch point
To calculate:
Use this formula:
(t)
(v
o
cos φ) t
y(t)
(v
o
sin φ) t  (g t
2
) / 2
v
x
(t)
v
o
cos φ
v
y
(t)
v
o
sin φ  g t
v(t)
v
0
2
 2
gtv
0
sin
φ
+
g
2
t
2
h
(v
o
2
sin
2
φ) / (2 g)
R
v
o
T cos φ
T
(2(
h

b
))
g
(v
o
sin φ) / g +
Actually, the only formula that has changed is that for
T
, where it has been revised to
account for the difference in elevation between the target and the launch point.
In the third type of problem, the target is located on a plane lower than the launch point;
in
Figure 63
, the target's
y
coordinate is lower than the launch point's
y
coordinate.