Complete question:
A bullet 2 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?
Answer:
The average acceleration of the bullet through the board is -4.083 x 10⁵ m/s²
Explanation:
Given;
initial velocity of the bullet, u = 420 m/s
final velocity of the bullet, v = 280 m/s
length of the bullet, d₁ = 2 cm
thickness of the board, d₂ = 10 cm
total distance penetrated by the bullet through the board;
d = d₁ + d₂ = 2 cm + 10 cm = 12 cm = 0.12 m
The average acceleration of the bullet through the board is calculated as;
[tex]v^2 = u^2 + 2ad\\\\2ad = v^2 - u^2\\\\a = \frac{v^2 - u^2}{2d} \\\\a = \frac{(280^2) - (420^2)}{2(0.12)} = -4.083 \times 10^{5} \ m/s^2[/tex]
Therefore, the average acceleration of the bullet through the board is -4.083 x 10⁵ m/s²
