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Physics · WORK, ENERGY AND POWER
हिन्दीA test car of mass \( 1200\text{ kg} \) moving at a speed of \( 72\text{ km h}^{-1} \) on a smooth horizontal track collides with a horizontally mounted buffer spring of spring constant \( 4.8 \times 10^4\text{ N m}^{-1} \). The maximum compression of the spring is:
Correct answer · Option B
\( 3.16\text{ m} \)
Explanation
Speed \( v = 72 \times \frac{5}{18} = 20\text{ m s}^{-1} \). Conservation of energy: \( \frac{1}{2} k x_m^2 = \frac{1}{2} m v^2 \implies x_m = v\sqrt{\frac{m}{k}} = 20\sqrt{\frac{1200}{48000}} = 20\sqrt{\frac{1}{40}} = \frac{20}{6.325} \approx 3.16\text{ m} \).
