Explanation: \(1\text{ম ক্ষেত্র, } v^2 = u^2 - 2as \implies 2as = u^2 - v^2\) \(\implies a = \frac{u^2 - \left(\frac{1}{3}u\right)^2}{2s} = \frac{u^2 - \frac{u^2}{9}}{2s} = \frac{8u^2}{18s} = \frac{u^2}{9s}\) \(\text{যেহেতু দুই তৃতীয়াংশ বেগ হ্রাস পায়, তাই শেষ বেগ হবে এক তৃতীয়াংশ অর্থাৎ } v = \frac{1}{3}u\) \(2\text{য় ক্ষেত্র, } v^2 = u^2 - 2as\) \(\implies 0 = u^2 - 2as \implies s = \frac{u^2}{2a}\) \(\implies s = \frac{\left(\frac{1}{3}u\right)^2}{2 \times \frac{u^2}{9s}} = \frac{\frac{u^2}{9}}{\frac{2u^2}{9}} = \frac{1}{2} = 0.5\) \(\text{Ans. (A)}\)