일반물리학 1 — Motion in Two and Three Dimensions: Problem 23

23 A shell, which is initially located at a distance of 40.4 m above a horizontal plane, is fired horizontally with a muzzle velocity of 285 m/s to strike a target on the horizontal plane. (a) How long does the projectile remain in the air? (b) At what horizontal distance from the firing point does the shell strike the plane? What are the magnitudes of the (c) horizontal and (d) vertical components of its velocity as it strikes the ground?