• • Consider the motion of a projectile in the vertical plane, assume that the ground is a horizontal plane and the gravitational acceleration is 9.8m/s2 , and the atmospheric density is ρ=1.29kg/m³ . The mass of the projectile is 50kg, the drag coefficient CD=0.1, and the upwind cross-sectional area S=0.03m² . The initial velocity magnitude is 100m/s, the firing Angle (the Angle between the initial velocity direction and the horizontal plane) is 40degree, and the initial height of the projectile is zero. Establish the differential equations of the two-dimensional motion of the projectile horizontal displacement, vertical displacement, velocity changes with time, the motion trajectory diagram.

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