Physics

Problem

Two ports

A

and

B

are located on the same bank of a river, separated by distance

D

. A boat travels from

A

B

(downstream) and immediately crosses the river to point

C

directly opposite

B

. The river width is

w

. If boat speed is

v

and river speed is

u

, find the total time taken for the journey

A \to B \to C

. Assume for the crossing part (

B \to C

) the boat steers to minimize drift (zero drift).