Question

A bullet fired into a thick block loses half of its velocity after penetrating 3 cm. The total length penetrated by the bullet before it comes to rest inside the block is :

• A. 3 cm
• B. 5 cm
• C. 4 cm
• D. 6 cm

Answer 1

Answer: (C)

4 cm

$v^2=u^2+2as$

${\left(\frac{u}{2}\right)}^2=u^2-2a\ast 3$

$\frac{3u^2}{4}=6a$

$u^2=8a$

$v^2=u^2+2as$

$0^2=u^2-2as$

$0=8a-2as$

$s=\frac{8a}{2a}$

$s=4cm$

Hence option 'C' is correct.