Question

A bullet fired into a wooden block, loses half of its velocity after penetrating 90 cm. Before coming to rest it penetrates a further distance of –

• A. 10 cm
• B. 20 cm
• C. 30 cm
• D. 60 cm

Answer 1

Answer: (C)

30 cm

Answer 2

(v/2)² = v² – 2a (90)

 180a = $\frac{3}{4}v^{2}$ ……(1)

0 = $\left( \frac{v}{2} \right)^{2}$ – 2ax

 2ax = v²/4 ……..(2)

From (2)/(1), $\frac{2ax}{180a}$ = $\frac{v^{2}/4}{3v^{2}/4}$

 x = 30 cm