Acamera operator is filming a nature explorer in the rocky mountains. the explorer needs to swim across a river to his campsite. by watching debris flowing down the river, the operator estimates that the stream is flowing at 0.633 m/s0.633 m/s . in still water, the explorer can swim at 0.739 m/s0.739 m/s . at what angle, less than 90°, with respect to the shoreline should the operator advise him to swim so that he travels directly across the stream to his campfire?