Question

A ferry is crossing a river.The ferry is headed due north with a speed of 2.5 m/s relative to the water and the river's velocity is 2.0 m/s to the east. What is the magnitude and direction of the ferry's velocity relative to Earth.
( Give the angle from east 0 degrees )

Answer 1

Ferry velocity with respect to earth =
Ferry velocity with respect to water + water velocity with respect to earth

magnitude = sqrt[2.5^2 + 2.0^2]
= 3.20 m/s

direction = arctan(2.5/2)
= 51.3 degrees north of east.