Understanding the Concepts

* Deceleration: This is the rate at which an object slows down. It's the negative of acceleration.

* Uniform Deceleration: We'll assume the bullet experiences a constant deceleration as it penetrates the wall.

* Kinematics Equations: We'll use the following kinematics equation:

* v² = u² + 2as (where v = final velocity, u = initial velocity, a = acceleration, s = distance)

Calculations

1. Convert units:

* The distance (5 cm) needs to be in meters: 5 cm = 0.05 m

2. Set up the equation:

* Final velocity (v) = 0 m/s (the bullet stops)

* Initial velocity (u) = 20 m/s

* Distance (s) = 0.05 m

* Acceleration (a) = deceleration (since it's slowing down)

The equation becomes: 0² = 20² + 2 * a * 0.05

3. Solve for acceleration (deceleration):

* 0 = 400 + 0.1a

* -400 = 0.1a

* a = -4000 m/s²

Answer:

The deceleration of the bullet within the wall is 4000 m/s². The negative sign indicates that the bullet is slowing down.