Magnetic Effects Of Current Question 3
Question 3 - 2024 (27 Jan Shift 1)
Position of an ant ( $\mathrm{S}$ in metres) moving in $\mathrm{Y}-\mathrm{Z}$ plane is given by $\mathrm{S}=2 \mathrm{t}^{2} \hat{\mathrm{j}}+5 \hat{\mathrm{k}}$ (where $\mathrm{t}$ is in second). The magnitude and direction of velocity of the ant at $t=1 \mathrm{~s}$ will be :
(1) $16 \mathrm{~m} / \mathrm{s}$ in $y$-direction
(2) $4 \mathrm{~m} / \mathrm{s}$ in $\mathrm{x}$-direction
(3) $9 \mathrm{~m} / \mathrm{s}$ in z-direction
(4) $4 \mathrm{~m} / \mathrm{s}$ in y-direction
Show Answer
Answer: (4)
Solution:
$\vec{v}=\frac{d \vec{s}}{d t}=4 t \hat{j}$
At $\mathrm{t}=1 \sec \overrightarrow{\mathrm{v}}=4 \hat{\mathrm{j}}$
