What is the test for establishing "force" as an element of robbery?

force' means 'force, not actual or direct, exerted upon the person robbed, by operating upon [a] fear of injury . . . .' [Citation.] . . . [] As we have noted, 'force' is not an element of robbery independent of 'fear'; there is an equivalency between the two. '"[T]he coercive effect of fear induced by threats . . . is in itself a form of force, so that either factor may normally be considered as attended by the other."' [Citation.]" (People v. Wright (1996) 52 Cal.App.4th 203, 210-211.)

"'The element of fear for purposes of robbery is satisfied when there is sufficient fear to cause the victim to comply with the unlawful demand for his property.' [Citations.] It is not necessary that there be direct proof of fear; fear may be inferred from the circumstances in which the property is taken. [Citation.] [] If there is evidence from which fear may be inferred, the victim need not explicitly testify that he or she was afraid. [Citation.] Moreover, the jury may infer fear '"from the circumstances despite even superficially contrary testimony of the victim."' [Citations.] [] The requisite fear need not be the result of an express threat or the use of a weapon. [Citations.] Resistance by the victim is not a required element of robbery [citation], and the victim's fear need not be extreme to constitute robbery [citation]. All that is necessary is that the record show '"'conduct, words, or circumstances reasonably calculated to produce fear . . . .'"' [Citation.] [] Intimidation of the victim equates with fear. [Citation.] An unlawful demand can convey an implied threat of harm for failure to comply, thus supporting an inference of the requisite fear. [Citation.]" (People v. Morehead (2011) 191 Cal.App.4th 765, 774-775.)