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In 2006, NASA’s Mars Odyssey orbiter detected violent gas eruptions on Mars, where the acceleration due to gravity is 3.7 m/s2. The jets throw sand and dust about 62.0 m above the surface. Scientists estimate that the jets originate as high-pressure gas speeds through vents just underground at about 130 km/h. How much energy per kilogram of material is lost due to nonconservative forces as the high-speed matter forces its way to the surface and into the air? (Express your answer to two significant figures.)

Respuesta :

Answer:

The unit energy losses due to nonconservative forces is 881.40 joules per kilogram.

Explanation:

We can estimate the unit energy losses of gas eruption by Principle of Energy Conservation and Work-Energy Theorem:

[tex]U_{g,1} + K_{1} = U_{g,2}+K_{2}+W_{loss}[/tex] (Eq. 1)

Where:

[tex]U_{g,1}[/tex] - Gravitational potential energy of gas eruptions at surface, measured in joules.

[tex]U_{g,2}[/tex] - Gravitational potential energy of gas eruptions at highest height, measured in joules.

[tex]K_{1}[/tex] - Translational kinetic energy of gas eruptions at surface, measured in joules.

[tex]K_{2}[/tex] - Translational kinetic energy of gas eruptions at highest height, measured in joules.

[tex]W_{loss}[/tex] - Energy losses due to nonconservative forces, measured in joules.

We clear the component associated with energy losses in (Eq. 1):

[tex]W_{loss} = U_{g,1}-U_{g,2}+ K_{1}-K_{2}[/tex]

And we expand it afterwards:

[tex]W_{loss} = m\cdot g\cdot (z_{1}-z_{2}) + \frac{1}{2}\cdot m \cdot (v_{1}^{2}-v_{2}^{2})[/tex] (Eq. 2a)

[tex]w_{loss} = g\cdot (z_{1}-z_{2})+\frac{1}{2}\cdot (v_{1}^{2}-v_{2}^{2})[/tex] (Eq. 2b)

Where:

[tex]W_{loss}[/tex] - Energy losses due to nonconservative forces, measured in joules.

[tex]w_{loss}[/tex] - Unit energy losses due to nonconservative forces, measured in joules per kilogram.

[tex]g[/tex] - Gravitational acceleration, measured in meters per second.

[tex]z_{1}[/tex], [tex]z_{2}[/tex] - Bottom and top height, measured in meters.

[tex]v_{1}[/tex], [tex]v_{2}[/tex] - Gas eruption speeds at surface and highest heights, measured in meters per second.

If we know that [tex]g = 3.7\,\frac{m}{s^{2}}[/tex], [tex]z_{1} = 0\,m[/tex]. [tex]z_{2} =62\,m[/tex]. [tex]v_{1} = 36.111\,\frac{m}{s}[/tex] and [tex]v_{2} = 0\,\frac{m}{s}[/tex], the unit energy losses are:

[tex]w_{loss} = \left(3.7\,\frac{m}{s^{2}} \right)\cdot (62\,m-0\,m)+\frac{1}{2} \cdot \left[\left(36.11\,\frac{m}{s} \right)^{2}-\left(0\,\frac{m}{s} \right)^{2}\right][/tex]

[tex]w_{loss} = 881.40\,\frac{J}{kg}[/tex]

The unit energy losses due to nonconservative forces is 881.40 joules per kilogram.

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