Question

Question #8328e

Answer 1

While running up the hill,his velocity vector is `(2i+3j) m/s`

And velocity of rain w.r.t the man is `-4j m/s`

So,velocity of rain w.r.t ground is `-4j+(2i+3j) m/s=2i-j m/s` (as velocity of rain w.r.t man = velocity of rain - velocity of man,so velocity of rain = velocity of rain w.r.t man + velocity of man)

While running down the hill,his velocity vector becomes `-(2i+3j) m/s`

So,velocity of rain w.r.t the man while going down is = velocity of rain - velocity of man `= 2i-j-(-2i-3j)=4i+2j m/s`

Hence the speed is `sqrt(4^2+2^2) m/s` i.e `sqrt(20) m/s`