A rocket takes off from Earth and reaches a speed of 105 m/s in 18.0 s. If the exhaust speed is 1,200 m/sand the mass of fuel burned is 110 kg, what was the initial mass (in kg, including the initial fuel) of the rocket?

Respuesta :

Answer:

The initial mass of the rocket is 526.2 kg.

Explanation:

Given that,

Final speed = 105 m/s

Time = 18.0 s

Exhaust initial speed = 1200 m/s

Mass of burned fuel = 110 kg

We need to calculate the initial mass

The velocity change of rocket under gravity is defined as,

[tex]v=u\ ln(\dfrac{m_{i}}{m})-gt[/tex]....(I)

We know that,

[tex]m=m_{i}-m_{bf}[/tex]

Put the value of m in equation (I)

[tex]v=u\ ln(\dfrac{m_{i}}{m_{i}-m_{bf}})-gt[/tex]

[tex]m_{i}=\dfrac{m_{bf}}{1-e^-{\dfrac{v+gt}{u}}}[/tex]

[tex]m_{i}=\dfrac{110}{1- e^-{\frac{105+9.8\times18}{1200}}}[/tex]

[tex]m_{i}=526.2 kg[/tex]

Hence, The initial mass of the rocket is 526.2 kg.

The initial mass of the rocket including the initial fuel is 1257.14 kg.

Conservation of linear momentum

The initial mass of the rocket is determined by applying the principle of conservation of linear momentum as follows;

m₁v₁ = m₂v₂

105m = 1200 x 110

105 m = 132,000

m = 132,000/105

m = 1257.14 kg

Thus, the initial mass of the rocket including the initial fuel is 1257.14 kg.

Learn more about conservation of linear momentum here: https://brainly.com/question/7538238