Question

Vanessa can swim 3.0 m/s in still water. While trying to swim directly across a river from west to east, Vanessa is pulled by a current flowing southward at 2.0 m/s.
A) What is the magnitude of Vanessa’s resultant velocity?
B) If Vanessa wants to end up exactly across stream from where she began, at what angle to the shore must she swim upstream?

Answer 1

X = 3 m/s.
Y = -2 m/s.

a. (Vr)^2 = X^2 + Y^2 = 3^2 + (-2)^2=13
Vr = 3.61 m/s. = Resultant velocity.

b. tan A = Y/X = -2/3 = -0.66666
A = -33.7o = 33.7o S. of E.
Therefore, she must swim 33.7o N. of E.