Answer:
Step-by-step explanation:
The acceleration can be calculated using the following formula:
acceleration = (final velocity - initial velocity) / time
In this case:
acceleration = (3 m/s - 15 m/s) / 2 seconds = -6 m/s^2
So the horse slows down with an acceleration of -6 meters per second squared. Note that the negative sign indicates that the direction of the acceleration is opposite to the direction of motion.