Final answer:
A 100-lb force directed vertically downward is considered a B. compression force, not tension, shear, or torque.
Step-by-step explanation:
The question pertains to the type of force being applied in a specific scenario. When a 100-lb force is directed vertically downward, it is considered a compression force. This type of force acts to compact or compress the object it is applied to. It is not a tension force, which would act to stretch or pull apart the object, nor is it shear force, which is applied parallel to the surface of an object causing parts of it to slide past one another. Torque is also not the correct type because torque refers to a force that causes rotation about an axis, which is not indicated by the downward vertical force described.
The type of force that is applied when a 100-lb force is directed vertically downward is Tension force.
When an object is hanging from a string, rope, or any other flexible material, the force applied on the object is called tension force. In this case, the 100-lb force is acting downward, creating tension on the rope or string.
Examples of tension force can be seen when lifting objects with a pulley system, suspending a piñata from a tree branch, or using a fishing line to reel in a fish.