A 30 kg girl and a 40 kg boy stand on roller skates, face one another, and push off each other. If the boy accelerates backward with an acceleration
of 6 m/s2, what will be the acceleration of the girl?

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