That is incorrect. The KE of the bullet is never equal to that of the pendulum. KE is not conserved over the collision. Forget mixing pendulum and bullet KE's.So, I did Ek(bullet) = Ek(pendulum)<-- found velocity, I used this for the momentum of the pendulum.
Before the collision the bullet has a constant KE assuming that there's no air friction.
The bullet and block are never one object moving with the same velocity. Simply occupying the same space does not countAnd what are some other possibilities of finding the initial velocity of the pendulum. why didnt 300(0.01) = (2.21)V' work? Because for a brief instant that the bullet does hit the block or the slight second its leaving the bullet is in the block, and momentum should be transferred no ?
Energy is only conserved for perfectly elastic collisions. Otherwise, energy is always lost in the collision to various "loss" pathways such as frictional heating, sound, plastic deformation of materials, breaking of atomic bonds(tearing, breaking), and so on.I dont fully understand why EK(bullet) = EK(bullet) + EP(bullet) doesnt work. The kinetic energy before and after the collision is constant, and so it the EP that the pendulum has. Why isnt the energy of the system being conserved.