A 4.00 kg model rocket is launched, shooting 50.0 g of burned fuel from its exhaust at an
average velocity of 625 m/s. What is the velocity of the rocket after the fuel has burned?
(Ignore effects of gravity and air resistance.)
Let m1 be the mass of the rocket, m2 - the mass of burned fuel. V1 - velocity of the rocket after the fuel has burned, V2 - average velocity of burned fuel. According to the law of conservation of linear momentum: