Two satellites, X and Y, are orbiting Earth. Satellite X is 1.2 × 106 m from Earth, and Satellite Y is 1.9 × 105 m from Earth. Which best compares the satellites? Satellite X has a greater period and a faster tangential speed than Satellite Y. Satellite X has a greater period and a slower tangential speed than Satellite Y. Satellite X has a shorter period and a faster tangential speed than Satellite Y. Satellite X has a shorter period and a slower tangential speed than Satellite Y.

Respuesta :

Answer: Satellite X has a greater period and a slower tangential speed than Satellite Y

Explanation:

According to Kepler’s Third Law of Planetary motion “The square of the orbital period of a planet is proportional to the cube of the semi-major axis (size) of its orbit”.

[tex]T^{2}=\frac{4\pi^{2}}{GM}r^{3}[/tex]    (1)

Where;

[tex]G=6.674(10)^{-11}\frac{m^{3}}{kgs^{2}}[/tex] is the Gravitational Constant

[tex]M=5.972(10)^{24}kg[/tex] is the mass of the Earth

[tex]r[/tex]  is the semimajor axis of the orbit each satellite describes around Earth (assuming it is a circular orbit, the semimajor axis is equal to the radius of the orbit)

So for satellite X, the orbital period [tex]T_{X}[/tex] is:

[tex]T_{X}^{2}=\frac{4\pi^{2}}{GM}r_{X}^{3}[/tex]    (2)

Where [tex]r_{X}=1.2(10)^{6}m[/tex]

[tex]T_{X}^{2}=\frac{4\pi^{2}}{(6.674(10)^{-11}\frac{m^{3}}{kgs^{2}})(5.972(10)^{24}kg)}(1.2(10)^{6}m)^{3}[/tex]    (3)

[tex]T_{X}=413.712 s[/tex]    (4)

For satellite Y, the orbital period [tex]T_{Y}[/tex] is:

[tex]T_{Y}^{2}=\frac{4\pi^{2}}{GM}r_{Y}^{3}[/tex]    (5)

Where [tex]r_{Y}=1.9(10)^{5}m[/tex]

[tex]T_{Y}^{2}=\frac{4\pi^{2}}{(6.674(10)^{-11}\frac{m^{3}}{kgs^{2}})(5.972(10)^{24}kg)}(1.9(10)^{5}m)^{3}[/tex]    (6)

[tex]T_{Y}=26.064 s[/tex]    (7)

This means [tex]T_{X}>T_{Y}[/tex]

Now let's calculate the tangential speed for both satellites:

For Satellite X:

[tex]V_{X}=\sqrt{\frac{GM}{r_{X}}}[/tex] (8)

[tex]V_{X}=\sqrt{\frac{(6.674(10)^{-11}\frac{m^{3}}{kgs^{2}})(5.972(10)^{24}kg)}{1.2(10)^{6}m}}[/tex]

[tex]V_{X}=18224.783 m/s[/tex] (9)

For Satellite Y:

[tex]V_{Y}=\sqrt{\frac{GM}{r_{Y}}}[/tex] (10)

[tex]V_{Y}=\sqrt{\frac{(6.674(10)^{-11}\frac{m^{3}}{kgs^{2}})(5.972(10)^{24}kg)}{1.9(10)^{5}m}}[/tex]

[tex]V_{Y}= 45801.13 m/s[/tex] (11)

This means [tex]V_{Y}>V_{X}[/tex]

Therefore:

Satellite X has a greater period and a slower tangential speed than Satellite Y

Answer:

B

Explanation: