Question

In fireworks when a rocket is set on fire it flies and also the center of mass moves in parabolic path , is it because center of mass also have the kinetic energy ? If not , then in second situation where a bomb is placed on a pole above the ground ,after the blast the center of mass moves down , so is that containing potential energy ?
plz explain .

Answer 1

Actually, the mass on the pole doesn't move down, it doesnt move anywhere initially. The individual pieces move in all directions because in an explosion momentum is conserved and the center of mass itself stays put. Upon explosion, however, it is no longer connected to the pole. The pieces that have exploded are simply under the influence of gravity and their initial velocities after explosion, so they will the move in a parabolic motion until they reach the ground.

Answer 2

ok

Answer 3

actually my question was the bomb is at rest so the center of mass , and rocket was moving or have kinetic energy so the center of mass, but when bomb explodes the particles scatter down now my question is which force draws the center of mass down along with particle , is center of mass just an imagination if its not there must be something which draws that to the earth .

Answer 4

the center of mass will still move in a parabolic motion but will be under the influence of things like air resistance. Once there is no thrust, the body as a whole will move in a parabolic motion, but remember that once it is exploded, the particles WILL spread out in all directions because momentum must be conserves, but they seem to simply fall because they are no longer have any thrust at that point and also, the particles are lighter than the whole which means less inertia which means that things like air resistance play a more significant role in slowing it down.

Answer 5

that i understood , so this means the center of mass is a thing for which momentum must be conserved ?