Question

A bullet 2.00 cm long is fired at 420𝑚/𝑠 and passes straight through a 10.0 cm thick board, exiting at 280𝑚/𝑠. What is the average acceleration of the bullet through the board?

a. -490,000 m/ s²

b. 196,000 m/ s²

c. -1,400 m/ s²

d. -700 m/s²

Answer 1

The average acceleration of the bullet through the board

$$a=\frac{v_f^2-v_i^2}{2d}$$

$$a=\frac{280^2-420^2}{2*0.10}=-490\:000\:\rm m/s^2$$

Answer: A