The rocket, weighing 400 g, rose vertically to a height of 125 m with complete combustion of fuel.

The rocket, weighing 400 g, rose vertically to a height of 125 m with complete combustion of fuel. The mass of the fuel is 50 g. Determine the rate of release of gases from the rocket.

Data: m1 (rocket mass) = 400 g (0.4 kg); h (the height to which the rocket rose vertically) = 125 m; m2 (fuel mass) = 50 g (0.05 kg).
Constants: g (acceleration due to gravity) ≈ 10 m / s2.
1) Determine the initial velocity of the rocket ascent: Ep = Ek = m1 * g * h = m1 * Vp2 / 2, whence Vp = √ (2 * g * h) = √ (2 * 10 * 125) = 50 m / s.
2) Let us calculate the gas exit velocity: m1 * Vr = m2 * Vg and Vg = m1 * Vr / m2 = 0.4 * 50 / 0.05 = 400 m / s.
Answer: The speed at which gases exit from the rocket is 400 m / s.