Final answer:
A single incidence angle and a single refractive angle are necessary when considering just the surface in compound angle problems. Components perpendicular and parallel to the surface are important for resolving forces or velocities.
Step-by-step explanation:
When just the surface must be considered in compound angle problems, a single incidence angle and a single refractive angle are required. In the context of optics or physics problems dealing with refraction at a surface, understanding the relationship between incident light rays and the surface is crucial for solving compound angle problems. The angle of incidence is the angle between the incident ray and the normal to the surface, while the angle of refraction is the angle between the refracted ray and the normal.
Components of forces or velocities perpendicular and parallel to surfaces are often involved in physics problems. To find these components, one can use trigonometric functions such as sine and cosine, which relate the angles to the lengths of sides in a right triangle. For example, if an object impacts a surface at an angle, the force or velocity components can be resolved into perpendicular (θ₁) and parallel (θ₂) components relative to the surface.
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