Editing Projectile motion (section)

=== Displacement in polar coordinates ===
The parabolic trajectory of a projectile can also be expressed in polar coordinates instead of [[Cartesian coordinate system|Cartesian]] coordinates. In this case, the position has the general formula
:<math> r( \phi ) = \frac{2v_0^2 \cos^2\theta}{|g|} \left(\tan\theta\sec\phi -\tan\phi\sec\phi \right)  </math>.
In this equation, the origin is the midpoint of the horizontal range of the projectile, and if the ground is flat, the parabolic arc is plotted in the range <math> 0 \leq \phi \leq \pi </math>. This expression can be obtained by transforming the Cartesian equation as stated above by <math> y = r \sin\phi </math> and <math> x = r \cos\phi </math>.