Theory If we neglect the air resistance, the flight path of a projectile launched at an initial speed vo and an angle of departure relative to the horizontal is a parabola (see Fig. 1) Figure 1: Flightpath of a projectile If we assume that the projectile is launched from the surface of the Earth, i.e., at yo-0, then the altitude of the projectile as a function of time is , where g-9.81 m/sis the gravitational constant, is time (in seconds), and V-Vo sin (in meters per second). The distance of the projectile from the launching position as a function of time is x(t)-Ut, where U-vo cos The velocity of the projectile in the horizontal direction, i.e., parallel to the x-axis, IS u(t)U, and the velocity in the vertical direction, i.e., parallel to the y-axis, is If we include the effects of air resistance, then the altitude of the projectile as a function of time can be approximated as where k is the coefficient of resistance (with the unit 1/s). The distance of the projectile relative to the initial position as a function of time is kt The velocity of the projectile in the horizontal direction is u(t)Uekt, and in the vertical direction