1. The problem statement, all variables and given/known data A particle of mass m is thrown vertically upwards with initial speed v. When the particle returns to it starting point, what are the changes in momentum and kinetic energy of the particle. 2. Relevant equations P=mv KE=1/2mv2 3. The attempt at a solution The answer to this question is change in momentum = 2mv while there's no change in KE, but I really don't understand how to calculate them?