(a) find expressions for the speeds of the comet at perihelion and aphelion.
(b) evaluate these expressions for comet halley, and find the kinetic energy, gravitational potential energy, and total mechanical energy for this comet at perihelion and aphelion. take the mass of comet halley to be 2.2×1014kg.

Awater slide of length l has a vertical drop of h. abby's mass is m. an average friction force of magnitude f opposes her motion. she starts down the slide at initial speed vi. use work-energy ideas to develop an expression for her speed at the bottom of the slide. then evaluate your result using unit analysis and limiting case analysis. express your answer in terms of the variables h, m, l, vi, f and appropriate constants. vf v f