A person moves due east at speed 6m/s and feels the wind is blowing to south at speed 6 m/s.
(a) Find actual velocity of wind blow.
(b) If person doubles his velocity then find the relative velocity of wind blow w.r.t. man.

Explanation

(a) `vec_("act")=vecv_("rel")+vecv_("ref")`
`vecv_(w)=vecv_(wm)+vecv_(m)=-6j+6hati`
`vecv_(w)=6hati-6hatj`
`|vecv|=6sqrt(2) m//s` ans it blowing to S-E

(b) Person doubles its velocity then `vec_(m)=o12hati` but actual wind velocity
remain unchanged.
`vec_(wm)=vecv_(w)-vecv_(m)=(6hati-6hatj)-12hati`
`vecv_(wm)=-6hati-6hatj`
Now relative velocity of wind is `6sqrt(2)m//s` to S-W