Final answer:
The resistive force that keeps a screw in place and resists its motion is known as friction, specifically static friction when the screw is not moving. Friction arises from the roughness of contacting surfaces and the molecular forces between them.
Step-by-step explanation:
The force that resists motion when using a screw that keeps it in place is called friction. Friction is a resistive force that opposes relative motion between systems in contact. When a screw is tightened, the static friction between the threads of the screw and the material prevents the screw from loosening, thus maintaining its position. If the object were to move, friction arises due to both the mechanical interlocking of surface irregularities and the attractive forces between the molecules of the contacting surfaces, even if these surfaces appear smooth.
Static friction is the specific type that holds a stationary object in place relative to another object or surface, and it must be overcome to initiate motion. Kinetic friction, on the other hand, acts when objects are already in motion relative to one another. The concepts of friction and its types are fundamental in understanding how forces counteract motion in physical systems.