A bullet is fired into a fixed target looses one third of its velocity after travelling 4 cm. It penetrates further D×10⁻³ m before coming to rest. The value of D is .

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32. After 4 cm the speed is (2u)/3: ((2u)/3)² = u² - 2a(0.04) ⇒ 2a(0.04) = (5u²)/9. From (2u)/3 to rest: 0 = (4u²)/9 - 2ad ⇒ d = (4u²/9)/(2a). Divide: d/(0.04) = (4/9)/(5/9) = 4/5 ⇒ d = 0.032 m = 32×10⁻³ m. D = 32.

A bullet is fired into a fixed target looses one third of its velocity after travelling 4 cm. It penetrates further D×10⁻³ m before coming to rest. The value of D is ______.

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