Final answer:
The force of impact when a 40kg miniature horse running at 8 m/s comes to a stop in 0.5s is calculated using Newton's second law. The result is a force of -640 N, indicating an eastward direction opposite to the initial motion.
Step-by-step explanation:
The question asks for the force of impact when a 40kg miniature horse hits a fence and comes to a sudden stop. The force can be calculated using Newton's second law of motion, which states that force equals mass times acceleration (F=ma).
To find the acceleration, we need to use the formula for acceleration which is the change in velocity divided by the time it takes for that change (a = Δv / t). Here, the horse comes to a stop from 8 m/s, so Δv is -8 m/s (since it's coming to rest), and the time is given as 0.5 s. The acceleration is therefore -8 m/s divided by 0.5 s, resulting in -16 m/s². The negative sign indicates that the acceleration is opposite to the direction of the velocity, which is expected when coming to a stop.
To determine the force, multiply the mass of the horse (40 kg) by the calculated acceleration (-16 m/s²), leading to a force of impact of -640 N. The negative sign indicates that the force is directed eastward, opposite to the direction the horse was initially running.