Water flows over a waterfall 100m in height. consider 1kg of the water, and assume that no energy is exchanged between this 1kg and its surroundings. a. what is the potential energy of the water at the top of the waterfall relative to its base? b. what is the kinetic energy of the water just before it strikes the bottom? c. after 1kg of water enters the river below the falls, what change as occurred in its state? d. plot all pertinent properties (ke, .)

Emmy kicks a soccer ball up at an angle of 45° over a level field. she watches the ball's trajectory and notices that it lands, two seconds after being kicked, about 20 m away to the north. assume that air resistance is negligible, and plot the horizontal and vertical components of the ball's velocity as a function of time. consider only the time that the ball is in the air, after being kicked but before landing. take "north" and "up" as the positive ‑ and ‑directions, respectively, and use ≈10 m/s2 for the downward acceleration due to gravity.