Question

A $30g$ bullet initially travelling at $120m/s$ penetrates $12cm$ into a wooden block. The average resistance by the wooden block is

• A. $2850N$
• B. $22000N$
• C. $2000N$
• D. $1800N$

Answer 1

Answer: (D)

$1800N$

Let energy resistance = F

Work done by force of resistance $F=K.E$ of bullet

$F\times 12\times {10}^{-2}=\frac{1}{2}m{v}^2=\frac{1}{2}\times 30\times {10}^{-3}\times (120{)}^2$

$F=\frac{3}{24}\times (100{)}^2=1800N$