Question

a ferry which runs at 12m/s in still water travels between towns a and b on a river which flows south at 9 m/s. the ferry leavs a and heads due east but reaches the east bank at C. it then heads north to B. whatis the velocity of the ferry as it traverses route ac?

Answer 1

= 15 m/s

Step-by-step explanation:

Considering right side(west) as positive x-axis and south as negative y-axis.

velocity of boat in still water
`v_b=12\hat{i}`

velocity of stream
`v_s=-9\hat{j}`

now relative velocity of boat w.r.t. stream
`v_(b/s)=12\hat{i}+9\hat{j}`

this velocity with which ac distance will be covered.

therefore magnitude of
`v_(b/s) =√(12^2+9^2)`

= 15 m/s