- #1
Asad Raza
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Homework Statement
A rocket starts from rest in deep space. The rocket structure and systems weigh a total of 500kg and it has 500kg of fuel initially. When the engines are fired, fuel is ejected from the end of the rocket at a speed of 100m/s relative to the rocket.
How fast will the rocket be going when all the fuel is used up?
Homework Equations
F=DP/D
P1=P2 (Intial momentum equals final in absence of any external forces)
The Attempt at a Solution
The solution of this problem shows a mass being added up into the rocket and the mass being ejected. Then later on, the solution takes the mass at end m+dm and applies integral. How come be a such a large change modeled by dm or dv, i.e a small change? Also, how is the mass being added upto the rocket? Please answer these two questions descriptively. The picture is attached below
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