1. The problem statement, all variables and given/known data Suppose that the momentum of a system is 8 kg m/s. What is the kinetic energy of the system if it has a mass of 10kg? If this system is brought to rest with a constant force in 5 seconds, what is the magnitude of this force? 2. Relevant equations Momentum > p = (m)(v) Kinetic Energy > KE = 0.5(m)(v)2 3. The attempt at a solution Whenever I get an answer this easily, I am always very cautious, because it seems too easy and I usually get it wrong. So far, I applied the momentum equation, p = (m)(v) > 8 = 10v, and solved to get the fact that velocity is 4/5 m/s. Then, I plugged that into the formula for Kinetic Energy, KE = 1/2(m)(v)2, and I got that the Kinetic Energy is 16/5 Joules. As for finding the magnitude of the opposing force, I do not even know where to begin. Did I get the Kinetic Energy right, and how would I begin to find the opposing magnitude? Thanks!