Physics

Problem

A boat crosses a river of width

w = 1.2\,\text{km}

. The boat's speed relative to water is

v_{b} = 4\,\text{km/h}

and river speed is

v_{r} = 2\,\text{km/h}

. If the boat heads at an angle

\theta

with the normal such that the drift is minimized, what is the value of this minimum drift?