We all play on the roller coaster in playgrounds, but Ahmad suggested playing this game alone. Take point B as a reference level. Suppose Ahmad starts from rest at point A and moves downward towards point B. What happens to his gravitational potential energy as he moves downward?

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up

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

Suppose a soccer ball is kicked from the ground at an angle 20.0º above the horizontal at 8.00 m/s. the y-velocity is determined to be 2.74 m/s. how long will the ball be in the air? assume the ball lands at the same height at which it was kicked.