WARNING: Incoming Science LessonA throwing spear being thrown is not going to have as much kinetic energy than a throwing spear being stabbed.
False. If you observe the spear and only the spear, I would argue that a thrown one could have more KE. If you look at how someone throws a spear, they hold onto it for a long time, kinda like when pitching a baseball, and therefore it accelerates more than the stabbed spear since it is being held, and therefore sped up, for a longer period of time. Most stabs are relatively quick jabs compared to the larger sweeping motion required to hurl a spear at someone. Just imagine trying to throw a baseball by simply holding it parallel to your torso, then thrusting your arm straight out. That ball is going nowhere. But if you go through the entire motion, it can go pretty darn far at a much higher speed. Since both spears/baseballs have the same mass, the only difference would be their velocity. The one that you throw the 'proper' way has much more speed than the one you are thrusting with. Therefore, it has more KE.
the air friction from throwing would slow the projectile some
False, more or less. While air friction as you call it (more commonly known as air resistance or simply the viscosity of the air) does indeed exist, it can commonly be ignored for problems such as this one. Why? Well to be honest, air simply isn't that viscous. Something with high viscosity would be a liquid, like molasses. Heck, tar is even more viscous, taking somewhere around 80 years for it to drip a single drop when put in an inverted beaker. If you imagine having to wave your hand around through the air, sure you can feel the air move out of your way... now compare that to how it feels in a pool, or imagine how it would be in a pool filled with molasses. Much harder, I bet. The only time we would really consider air resistance is when throwing something that isn't at all aerodynamic. Think about when you drop a sheet of paper... it never just falls to the ground, it always floats around. That is based on its geometry as well as its weight. But I digress... in sports, you never see air resistance have much of an effect. The only sports that you might see it have some influence is in golf, football, maybe even baseball, if there are severe winds... but that isn't exactly 'air resistance' so much as it is simply an external force. Really, air resistance only helps frisbees, since air resistance provides lift.
tl;dr: Spears, sports balls, even throwing axes or knives, are all too aerodynamic to consider the viscosity of air. When was the last time that you threw a baseball and it stopped moving forwards BEFORE hitting the ground? Or when was the last time you got pitched a fast ball and it noticeably slowed right before you had to hit it because the air held it back? The only major force that affects projectiles would be gravity pulling them down. Now, we could get into how the spin on a baseball affects its trajectory, and air resistance is INDEED necessary for that, but that is for another day.
thrusting it would have your full body weight and kinetic motion from the transfer of energy of your body limbs into the spear as you thrust.
Ding ding ding! We have a winner! The only difference in thrusting with a spear and throwing it, is its total weight. As I said previously, examining ONLY the spear, a thrown one would travel faster and since they have the same weight, the thrown one would have more KE, and should therefore do more damage upon impact. However, we must not forget to look at the entire
system here. The thrown one has only its weight behind the impact. The stabbing one has both its weight, and the significantly larger weight of the person behind it. In crpg, the throwing lance has a weight of 1.5 kg. An average person might weigh ~82 kgs (180 lbs). If you stab with the throwing lance, with at least 75% of your weight behind it, it will do considerably more damage than any lightweight lance moving slightly faster through the air.
I didn't take physics
Okay I guess I can forgive you, but shame on you!