Comparing approximate solution of the ballistic problem with air resistance proportional to the square of the velocity, obtained by Johann Bernoulli in 1719, with numerical ones obtained through an analytical solution expressing the horizontal component of the velocity in terms of the angle between the tangent to the trajectory and the horizontal axis, it is found it to be sufficiently good for shooting angles so high as 20-. Results of practical interest are then calculated (football and tennis game among other cases) which may give elements to the physics teacher in this area, of knowing how good is his teaching usually ignoring air resistance.
