A butterfly is flying with a velocity 4 √2 m / s in North-East direction. Wind is slowly blowing at 1 m / s from North to South. The resultant displacement of the butterfly in 3 seconds is :

Question

A butterfly is flying with a velocity 4 √2 m / s in North-East direction. Wind is slowly blowing at 1 m / s from North to South. The resultant displacement of the butterfly in 3 seconds is : (A) 3 m (B) 20 m (C) 12 √2 m (D) 15 m

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/9aaf701d7d82e8f329dd9ba3b207d278-.png" /> vecVB W=4 √2 cos 45 hati+4 √2 sin 45 hatj =4 hati+4 hatj vecVw=- hatj vecVB= vecVB W+ vecVw=4 hati+3 hatj vecSB= vecVB × t=(4 hati+3 hatj) × 3=12 hati+9 hatj vecSB=√(12)2+(9)2=15 m

Q. A butterfly is flying with a velocity $42 m / s$ in North-East direction. Wind is slowly blowing at $1 m / s$ from North to South. The resultant displacement of the butterfly in $3$ seconds is :

$3 m$

$20 m$

$122 m$

$15 m$

$V_{B W} = 42 cos 45 \hat{i} + 42 sin 45 \hat{j}$
$= 4 \hat{i} + 4 \hat{j}$
$V_{w} = - \hat{j}$
$V_{B} = V_{B W} + V_{w} = 4 \hat{i} + 3 \hat{j}$
$S_{B} = V_{B} \times t = (4 \hat{i} + 3 \hat{j}) \times 3 = 12 \hat{i} + 9 \hat{j}$
$S_{B} = (12)^{2} + (9)^{2} = 15 m$

Q. A butterfly is flying with a velocity 42​m/s in North-East direction. Wind is slowly blowing at 1m/s from North to South. The resultant displacement of the butterfly in 3 seconds is :

3m

20m

122​m

15m