To find the acceleration, we can use the equation:
acceleration = (final velocity - initial velocity) / time
Given: Initial velocity (Vi) = 20 m/s south (let's consider south as the positive direction) Final velocity (Vf) = 20 m/s west Time (t) = 4 seconds
Since the final velocity is in a different direction than the initial velocity, we need to consider the vector components of the velocities separately. We can break down the final velocity into its north and west components.
The west component of the final velocity is 20 m/s, and since it is opposite to the positive direction, we consider it as negative.
Vf-west = -20 m/s
The north component of the final velocity is 0 m/s, as there is no velocity in the north direction.
Now, let's calculate the acceleration using the given formula:
acceleration = (Vf - Vi) / t
Acceleration = (-20 m/s - 20 m/s) / 4 s Acceleration = (-40 m/s) / 4 s Acceleration = -10 m/s²
Therefore, the acceleration is -10 m/s².