Question

complete the sentence below
if ( f_1 ) and ( f_2 ) are two forces simultaneously acting on an object, the vector sum ( f_1 + f_2 ) is called the
force.
if ( f_1 ) and ( f_2 ) are two forces simultaneously acting on an object, the vector sum ( f_1 + f_2 ) is called the
force.
if ( f_1 ) and ( f_2 ) are two forces simultaneously acting on an object, the vector sum ( f_1 + f_2 ) is called the
force.

Explanation:

In physics, when two forces \(F_1\) and \(F_2\) act on an object simultaneously, the vector sum \(F_1 + F_2\) is a well - defined concept. The term "resultant" is specifically used in the context of forces to denote the single force that would have the same effect as the combination of the two forces. The word "resulting" is more of a general term for something that follows as a consequence, "sum" is a very general mathematical operation word (not specific to forces), and "effective" is also a more general term (e.g., effective resistance in circuits, not as specific as "resultant" for forces).

Answer:

resultant