A bullet fired at a wooden block of thickness 0.15m manages to penetrate the block. If the mass of the bullet is 0.025kg and the average resisting force of the wood is 7.5 x 103N, calculate the speed of the bullet just before it hits the wooden block.
A. 450ms-1 B. 400ms-1 C. 300ms-1 D. 250ms-1
Correct Answer: C
Explanation
F = ma Therefore, a = \(\frac{F}{m}\) a = \(\frac{7.5 \times 10^{3}}{0.025}\) a = 3 x 105m/s2 using V2 = U2 + 2ax; V2 = 02 + (2 x 3 x 105 x 0.15) Therefore V = 300 m/s
