Final answer:
The term described by coplanar forces in opposite directions is compressive forces, which act towards each other, squeezing the object they are applied to. Tensile forces pull away, and shear forces are applied perpendicular to the object's length, causing sliding or deformation.
Step-by-step explanation:
The term described by coplanar forces in opposite directions is compressive forces. Compressive forces involve two or more forces that push towards each other, effectively squeezing the object to which they are applied. These are contact forces resulting from interatomic electric forces and have certain directions, typically acting along the line connecting the points of application. Contact forces also include tension, friction, normal force, and buoyant force. An example of compressive force is the force exerted on both ends of a column that is being compressed.
In contrast, tensile forces are forces that pull away from each other in opposite directions, causing tension in the object they are applied to, while shear forces are applied perpendicular to the length of an object and parallel to the cross-sectional area, trying to cause the object to slide or deform.