Q. What is a tangent?
A. A straight line which touches but one point on the circumference of a circle and is perpendicular to the radius at that point.
Q. Define angle of fall.
A. It is the angle which the tangent to the trajectory at the point of impact makes with a line parallel to the line of sight at this point.
Q. What is the line of departure?
A. The prolonged axis of the bore at the moment the projectile leaves the muzzle.
Q. What is the line of fire?
A. The prolonged axis of the bore before the gun is fired.
Q. What is the axis of the bore?
A. The line passing through the centre of the bore from breech to muzzle.