As we look up into the night sky, the moon and stars appear to move from east to west. This is because we are A) watching the sky rotate overhead, from east to west. B) viewing them from the surface of the rotating Earth. C) also moving on Earth in the same direction, east to west. D) orbiting on Earth around the Sun and nothing is really stationary.

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.