Using the diagram and these formulas, describe what will happen to the focal length if di is halved but do is doubled.
A) the focal length decreases
B) the focal length increases
C) the focal length is undetermined
D) the focal length remains unchanged

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.