3. One question that scientists tried to answer for many years dealt with planetary motion. How did they go about trying to determine the orbits of the planets? What were some of the models that were developed? What were the contributions of the various scientists discussed in the unit to our understandings of this topic? help me plz

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