Projectile Motion

The projectile motion concept is one of the more difficult concepts for students to comprehend. Also, it is also one of the more difficult concepts to teach. The teacher who teaches projectile need to learn the following ideas about this motion and its equations before tackling it otherwise the teacher falls into the trap of thinking that some equations involving it has "no solution,"

1. Equations for projectile motion are idealized setup and maybe difficult to perform and even verify in an outside set-up with a high degree of precision and accuracy.
2. To make the experiment less erroneous otherwise it might develop misconceptions to students is that the projectile in the projectile motion is also idealized (Actually a point-mass). The closest thing to a point mass in this experiment are the following - a marble, a metal ball or a small piece of stone. 
3. A plane or winged projectile follows a path not described by the kinematical equations. More so a rocket. A rocket loses mass as it it propelled and therefore does not follow a path described by the kinematical equations.  The more aerodynamically sound the device is, the less it follows the kinematical equations. Aerodynamical system is affected by air pressure. 
1. For example, a pingpong ball approximately follows the kinematical equations. However when a player applies strong SPIN to the ball, the ball either bounces higher or lower. In flight the ball curves its path either to the right, left, or drops fast or drops slower than usual,. The spin gave it aerodynamical effects.
2. The same idea works for BADMINTON bird. The :"ball" drops fast since the ball is dragged by the air so as it reaches its peak it drops almost vertically
4. The solutions for kinematical .equations sometimes need trigonometric identityes and property