Basic Biomechanics 7th Edition by Susan Hall

Exercise 2

A swimmer crossing a river proceeds at an absolute speed of 2.5 m/s on a course oriented at a 45° angle to the 1 m/s current. Given that the absolute velocity of the swimmer is equal to the vector sum of the velocity of the current and the velocity of the swimmer with respect to the current, what is the magnitude and direction of the velocity of the swimmer with respect to the current? (3.3 m/s at an angle of 32.6 ° to the current)