Let us review about rocket move

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Rocket motion is explained through Newton's third law and the conservation of momentum, where the rocket moves forward as gas is expelled backward. The discussion highlights that while total energy is conserved in a closed system, mechanical energy is not necessarily conserved due to the conversion of chemical energy into mechanical energy during fuel combustion. The presence of internal forces, such as the reaction of expelling gas, affects the mechanical energy balance. It is clarified that the conservation of energy principle applies, but it encompasses all forms of energy, not just mechanical. Understanding these principles is crucial for analyzing rocket propulsion dynamics.
gema
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Hello Forum,

Let us review about rocket move.The Rocket moving with 2 mechanical principe;Newton's 3 and conservation of momentum.If rocket at t=0 is in rest condition (E=0),after the gas with dm mass go out to the back from rocket ,then rocket move to the front(E=Ek1+Ek2).
Nothing external force in this system,

Energy of system is conserve, if nothing external force in the system.
But why the energy of system isn't conserve?
 
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gema said:
Energy of system is conserve, if nothing external force in the system.
But why the energy of system isn't conserve?
What do you mean by 'energy is conserved'? Just because there are no external forces, doesn't mean mechanical energy (for example) is conserved. You are converting chemical energy into mechanical energy by burning the fuel. (Total energy is conserved of course.)
 
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