Question

Two forces which cannot be replaced by a single force are said to form a

Answer 1

Answer:

A natural disaster is a major adverse event resulting from natural processes of the Earth; examples are floods, hurricanes, tornadoes, volcanic eruptions, earthquakes, tsunamis, storms, and other geologic processes

Answer 2

Answer:

By definition a couple is formed by two opposing and parallel forces, hence its resultant is 0.

From general vector field theory, an arbitrary force distribution can be substituted by one force (resultant) and a torque.

In the case of a couple it can be replaced by a single resultant torque.