Easy MCQ +4 / -1 PYQ · JEE Mains 2021

The planet Mars has two moons, if one of them has a period 7 hours, 30 minutes and an orbital radius of 9.0 $\times$ 103 km. Find the mass of Mars.

$$\left\{ {Given\,{{4{\pi ^2}} \over G} = 6 \times {{10}^{11}}{N^{ - 1}}{m^{ - 2}}k{g^2}} \right\}$$

  1. A 5.96 $\times$ 10<sup>19</sup> kg
  2. B 3.25 $\times$ 10<sup>21</sup> kg
  3. C 7.02 $\times$ 10<sup>25</sup> kg
  4. D 6.00 $\times$ 10<sup>23</sup> kg Correct answer

Solution

Option D is correct.<br><br>${T^2} = {{4{\pi ^2}} \over {GM}}.{r^3}$<br><br>$M = {{4{\pi ^2}} \over G}.{{{r^3}} \over {{T^2}}}$<br><br>by putting values<br><br>$M = 6 \times {10^{23}}$

About this question

Subject: Physics · Chapter: Gravitation · Topic: Satellites and Orbital Motion

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