A person with a blackbelt in karate has a fist that has a mass of 0.60 kg. Starting from rest, this fist attains a velocity of 9.0 m/s in 0.20 s. What is the magnitude of the average net force applied to the fist to achieve this level of performance?
My teacher hasn't given us notes and the book doesn't explain how to do anything... it just gives the questions and answers but that question isn't in the book.