Game Development Reference
In-Depth Information
Figure 6-3. Target lower than launch point
Table 6-3 shows the formulas to use for this type of problem. Here again, almost all of
the formulas are the same as those shown in Table 6-1 .
Table 6-3. Formulas—target lower than launch point
To calculate:
Use this formula:
x(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
b + (v o 2 sin 2 φ) / (2 g)
R
v o T cos φ
T
2 h
g
(v o sin φ) / g +
The only formulas that have changed are the formulas for h and T , which have been
revised to account for the difference in elevation between the target and the launch point
(except this time the target is lower than the launch point).
Finally, the fourth type of problem involves dropping the projectile from a moving
system, such as an airplane. In this case, the initial velocity of the projectile is horizontal
and equal to the speed of the vehicle dropping it. Figure 6-4 illustrates this type of
problem.