Final answer:
The crossing angle for pipelines should be as close to 90 degrees as practical. This helps to maintain pipeline integrity and facilitate maintenance. In physics, projectile motion is optimized at a 45-degree launch angle, while 0 degrees or 90 degrees launch angles result in no range.
Step-by-step explanation:
The crossing angle measured between an existing pipeline and the proposed location of a new pipe should be as close to 90 degrees as practical. This is recommended to minimize the potential for interference between the pipes and to ensure the structural integrity of the pipeline network. While other angles can be used, the 90-degree crossing minimizes the span where the pipes are in close proximity and may help in maintaining easier access for maintenance and inspection.
When discussing projectile motion, as illustrated by other questions related to physics, the angle of the projectile or the launch angle can greatly influence the behavior of the projectile. For instance, a projectile launched at 0 degrees or 90 degrees will have a range of zero because the projectile will either go straight up or horizontal without any vertical motion, respectively. The optimum angle to achieve the maximum horizontal distance is 45 degrees, assuming there is no air resistance and the projectile is launched from and lands on the same horizontal plane.