Answer
The Earth's new period of revolution would be $~~247~years$
Work Step by Step
In part (a), we found that the orbital speed would be $v = 121~m/s$
We can find the Earth's new period of revolution:
$T = \frac{2\pi~r}{v}$
$T = \frac{(2\pi)~(1.5\times 10^{11}~m)}{121~m/s}$
$T = 7.79\times 10^9~s$
$T = (7.79\times 10^9~s)[\frac{1~year}{(365)(24)(3600~s)}]$
$T = 247~years$
The Earth's new period of revolution would be $~~247~years$
