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Two Earth satellites, A and B, each of mass m = 940 kg , are launched into circular orbits around the Earth's center. Satellite A orbits at an altitude of 4500 km , and satellite B orbits at an altitude of 11100 km .
c) How much work would it require to change the orbit of satellite A to match that of satellite B?

Respuesta :

Answer:

The required work done is [tex]6.5\times10^{9}\ J[/tex]

Explanation:

Given that,

Mass of each satellites = 940 kg

Altitude of A = 4500 km

Altitude of B = 11100 km

We need to calculate the potential energy

Using formula of potential

[tex]U_{A}=-\dfrac{Gm_{A}m_{E}}{r_{A}}[/tex]

Put the value into the formula

[tex]U_{A}=-\dfrac{6.67\times10^{-11}\times940\times5.98\times10^{24}}{6.38\times10^{6}+4.50\times10^{6}}[/tex]

[tex]U_{A}=-3.44\times10^{10}\ J[/tex]

We need to calculate the potential energy

Using formula of potential

[tex]U_{B}=-\dfrac{Gm_{B}m_{E}}{r_{A}}[/tex]

Put the value into the formula

[tex]U_{B}=-\dfrac{6.67\times10^{-11}\times940\times5.98\times10^{24}}{6.38\times10^{6}+11.10\times10^{6}}[/tex]

[tex]U_{B}=-2.14\times10^{10}\ J[/tex]

We need to calculate the value of [tex]k_{A}[/tex]

Using formula of [tex]k_{A}[/tex]

[tex]k_{A}=-\dfrac{1}{2}U_{A}[/tex]

Put the value into the formula

[tex]k_{A}=\dfrac{1}{2}\times3.44\times10^{10}[/tex]

[tex]k_{A}=1.72\times10^{10}\ J[/tex]

We need to calculate the value of [tex]k_{B}[/tex]

Using formula of [tex]k_{B}[/tex]

[tex]k_{B}=-\dfrac{1}{2}U_{B}[/tex]

Put the value into the formula

[tex]k_{B}=\dfrac{1}{2}\times2.14\times10^{10}[/tex]

[tex]k_{B}=1.07\times10^{10}\ J[/tex]

We need to calculate the work done

Using formula of work done

[tex]W=\Delta K+\Delta U[/tex]

[tex]W=(k_{B}-k_{A})+(U_{B}-U_{A})[/tex]

[tex]W=(-\dfrac{U_{B}}{2}+\dfrac{U_{A}}{2})+(U_{B}-U_{A})[/tex]

[tex]W=\dfrac{1}{2}(U_{B}-U_{A})[/tex]

Put the value into the formula

[tex]W=\dfrac{1}{2}\times(-2.14\times10^{10}+3.44\times10^{10})[/tex]

[tex]W=6.5\times10^{9}\ J[/tex]

Hence, The required work done is [tex]6.5\times10^{9}\ J[/tex]