A student has begun training for basketball tryouts by running every evening. Part of the run has a very steep hill. One evening, she was running down the hill at a very fast pace when she noticed a dog lying in the middle of her path. She tried to stop to avoid hitting the dog but it
was very difficult. With a lot of effort, she was able to stop right before running into the dog.
Explain why it was so difficult for the student to stop.