Answer
$2.00\times 10^3K$
Work Step by Step
We know that
$u=\sqrt{\frac{3RT}{M_n}}$
This can be rearranged as
$T=\frac{u^2M_n}{3R}$
We plug in the known values to obtain:
$T=\frac{(3.53\times 10^3)^2(4.003\times 10^{-3})}{3(8.31)}=2.00\times 10^3K$
