OnlineCBT
Physics · LAWS OF MOTION
हिन्दीA bomb shell of mass \( 15\text{ kg} \) moving along the positive x-axis at a speed of \( 12\text{ m/s} \) suddenly explodes into two fragments of masses \( 5\text{ kg} \) and \( 10\text{ kg} \). If the \( 5\text{ kg} \) fragment flies off along the positive y-axis with a speed of \( 48\text{ m/s} \), calculate the magnitude of the velocity vector of the \( 10\text{ kg} \) fragment immediately after the explosion.
Correct answer · Option A
\( 30\text{ m/s} \)
Explanation
By momentum conservation: \( 15(12\hat{i}) = 5(48\hat{j}) + 10\mathbf{v}_2 \implies 180\hat{i} = 240\hat{j} + 10\mathbf{v}_2 \implies \mathbf{v}_2 = 18\hat{i} - 24\hat{j}\text{ m/s} \). Magnitude \( |\mathbf{v}_2| = \sqrt{18^2 + (-24)^2} = \sqrt{324 + 576} = 30\text{ m/s} \).
