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QJEEM24Ph7b2c: JEE Main 2024 Physics - Class 11 JEEM24Ph7b2c Solution: A bullet is fired into a fixed target looses one third of its…

A bullet is fired into a fixed target looses one third of its velocity after travelling 4 cm4 \mathrm{~cm} . It penetrates further D×10−3 m\mathrm{D} \times 10^{-3} \mathrm{~m} before coming to rest. The value of D\mathrm{D} is :

Multiple Choice Options

  • A 23
  • B 32
  • C 42
  • D 52

Step-by-Step Verified Solution

amp;v2−u2=2aSamp;(2u3)2=u2+2(−a)(4×10−2)amp;4u29=u2−2a(4×10−2)amp;−5u29=−2a(4×10−2)…(1)amp;0=(2u3)2+2(−a)(x)amp;−4u29=−2ax…(2)\begin{aligned}& v^2-u^2=2 a S \\& \left(\frac{2 u}{3}\right)^2=u^2+2(-a)\left(4 \times 10^{-2}\right) \\& \frac{4 u^2}{9}=u^2-2 a\left(4 \times 10^{-2}\right) \\& -\frac{5 u^2}{9}=-2 a\left(4 \times 10^{-2}\right) \ldots(1) \\& 0=\left(\frac{2 u}{3}\right)^2+2(-a)(x) \\& -\frac{4 u^2}{9}=-2 a x \ldots(2)\end{aligned}

(1)/(2)(1)/(2)

amp;54=4×10−2xamp;x=165×10−2amp;x=3⋅2×10−2 mamp;x=32×10−3 m\begin{aligned}& \frac{5}{4}=\frac{4 \times 10^{-2}}{\mathrm{x}} \\& \mathrm{x}=\frac{16}{5} \times 10^{-2} \\& \mathrm{x}=3 \cdot 2 \times 10^{-2} \mathrm{~m} \\& \mathrm{x}=32 \times 10^{-3} \mathrm{~m}\end{aligned}

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