**Force Equations**
In
the above equations: v is velocity in
m/s, v_{0}
is initial velocity in m/s, a is
acceleration in m/s^{2}, t is
time in s, Δx and Δy are the change in
position in m, F is the force in J, m is
the mass in g, g is the acceleration of
gravity (9.8 m/s^{2}), ρ is the
fluid density in kh/m^{3}, CD is
the drag coefficient in N, and A is the
cross sectional area in m^{3}.

The

**ballistic
coefficient** determines how well a
projectile can overcome

**air resistance**
or drag. It is calculated as a ratio
comparing the performance of the ammunition
to a standard projectile. The higher the
ballistic coefficient, the better that the
ammunition is at resisting drag and wind
deflection. Usually, the longer the bullets
are, the higher the ballistic coefficient.