# Release Angle

The **Release Angle** is the angle that the velocity vector of the projectile reaches
before the projectile is released.

**Note:** The angle of the velocity of the projectile is not quite the same as the
angle of a vector perpendicular to the sling. The angle perpendicular to the sling is the velocity
of the projectile relative to the end of the arm, but the end of the arm is also moving, so the
velocity of the projectile will be the vector sum of the velocity at the end of the arm and the
relative velocity of the projectile.

The projectile typically goes the farthest if the release angle is between 35deg and 40deg.