Answer
a) satellite 2 has a greater orbital speed
b) $v=5.59Km/s$
c) $v=4.56Km/s$
Work Step by Step
(a) We know that the orbit speed and the radius are inversely proportional. Thus, the orbit speed decreases with increasing altitude. We conclude that satellite 2, which is at lower altitude than satellite 1, has a greater orbital speed.
(b) We know that
$v=\sqrt{\frac{GM_E}{R_E+h}}$
$\implies v=\sqrt{\frac{GM_E}{R_E+R_E}}$
We plug in the known values to obtain:
$v=\sqrt{\frac{(6.67\times 10^{-11})(5.97\times 10^{24})}{2\times 6.37\times 10^6}}$
$v=5590m/s=5.59Km/s$
(c) We know that
$v=\sqrt{\frac{GM_E}{R_E+h}}$
$\implies v=\sqrt{\frac{GM_E}{R_E+2R_E}}$
We plug in the known values to obtain:
$v=\sqrt{\frac{(6.67\times 10^{-11})(5.97\times 10^{24})}{3\times 6.37\times 10^6}}$
$v=4560m/s=4.56Km/s$
