A physics teacher turns the tube upside down very quickly and the small metal spheres then fall though 1.8m and hit the bottom of the tube calculate the decrease of gravitational potential as the spheres fall 1.8, decrease of gravitational potential=?

1. jay fills a wagon with sand (about 20 kg) and pulls it with a rope 30 m along the beach. he holds the rope 25° above the horizontal. the rope exerts a 20-n tension force on the wagon. how much work does the rope do on the wagon?

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

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration