Question

If a body loses half of its velocity on penetrating 3 cm in a wooden block then how much will it penetrate more before coming to rest?

• A. 1 cm
• B. 2 cm
• C. 3 cm
• D. 4 cm

Answer 1

Answer: (A)

Let initial velocity of body at point A is v. AB is 3 cm $v^2=u^2-2as$ ${\left(\frac{v}{2}\right)}^2=v^2-2a\times 3$ $a=\frac{v^2}{8}$ Let an penetrating 3 cm in a wooden block the body moves $x$ distance from B to C According to the question $u=\frac{v}{2}$ and $v=0$ $\therefore$ ${(0)}^2={\left(\frac{v}{2}\right)}^2-2\times \frac{v^2}{8}\times x$