Practice 5: Work & Kinetic Energy Problem 1. A box of mass m=1 kg is sliding with a constant speed of 4.5 m/s on a frictionless horizontal surface when, at point P, it encounters a rough section. The coefficient of kinetic friction there is 0.1 at P. How far this box slides before stopping. Vi m P 1. Hint: To apply the work-energy theorem, we need to know the change in kinetic energy. What is AE in this problem? PHYS1230: General Physics Problems Problem 2. Similar to Problem 1, but now the coefficient of kinetic friction in the rough section is not constant; it starts at 0.1 at P and increases linearly with distance past P, reaching a value of 0.6 at 12.5 m past point P. How far this box slides before stopping. Vi m P Hk (20)