A sledder has 800 J of potential energy and 200 J of kinetic energy at one point on a steep hill. How much kinetic energy will the sledder have at the bottom of the hill? (Assume negligible air resistance and friction.)

Answer 1

assuming that your potential energy is defined as zero at the bottom of the hill, all your energy is kinetic by the time you get there. 800 + 200 = 1000

Pert of this problem statement is missing though. In potentials, all you can define is differences. You have to define some point as zero.