a model rocket expels 50 g of oxidized fuel from its exhaust at an average velocity of 600 m/s. If the mass of the rocket is 4.0 kg, what is its vertical launch velocity?

7.8 m/s

Explanation:

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  :

0 = m1V1 - m2V2

V1 = V2*m2 / m1

V1 = 625*0.05/4 = 7.8125 m/s

So, the velocity of the rocket is 7.8 m/s.

Hope this helps, have a nice day :D

cant without the picture! ?

i'm on my way to history not a mistory.