Is the change in position of an object in flight. Maximum vertical needs above 45 degrees and maximum horizontal needs below 45 (36-37 is optimal) Height of the center of gravity at takeoff. Give 3 examples of sports that use vertical with some horizontal movement. Horizontal air resistance (drag), ground friction and gravity. Gravity and drag change the trajectory of objects in flight. Describe the velocity and acceleration differences in both the x and z axes. X velocity is constant therefore no acceleration. Z velocity is constantly changing therefore there is always a different acceleration at each point in time due to the force of gravity. Vf = vi + at -> in x direction the final is equal to the initial. Vf^2 = vi^2 + 2ad -> in x direction final is initial. Df = vit + 2at^2 -> in x direction distance is the initial times the time.