Answer to Question #242644 in Classical Mechanics for eyad bahgat

Question

The same boat (𝑣𝐵𝑊 = 1.85 𝑚/𝑠 ) now heads directly across the river whose current is still 1.2 𝑚/𝑠. 

Answer 1

The resultant force (as seen by the observer on the bank):

$$v=\sqrt{1.85^2+1.2^2}=2.21\text{ m/s}$$