Q 11-03-131JEE MainJEE Main 2021 (20 Jul, Shift 1)Easy
A butterfly is flying with a velocity $4\sqrt2\ \text{m s}^{-1}$ in north-east direction. Wind is slowly blowing at $1\ \text{m s}^{-1}$ from north to south. The resultant displacement of the butterfly in 3 seconds is:
Answer: (D) 15 m
Take east as $\hat i$ and north as $\hat j$. Butterfly: $4\sqrt2$ along north-east $= 4\hat i + 4\hat j$. Wind: $-\hat j$.
Resultant velocity $= 4\hat i + 3\hat j$, magnitude 5 m/s. Displacement in 3 s $= 15$ m.
Solution by Sreeraj P, M.Sc Physics