In an anniversary celebration of Marilyn Bell's 1954 crossing of Lake Ontario a swimmer set out from the shores of New York and maintained a velocity of 4m/s [N]. As the swimmer approached the Ontario shore, she encountered a cross current of 2m/s [E 25deg S]. Find her velocity with respect to the crowd observing from the beach. Let North and East be positive and let S represent the swimmer, W for water and G for the observers on the ground. To be honest I don't have a clue where to start. I'm not even sure that my vector diagram is correct. I'm having trouble grasping this concept. My text is very discreet on explaining this concept.