Answer
$v_{rms}=3.4\frac{cm}{s}$
Work Step by Step
We know that
$v_{rms}=\sqrt\frac{\Sigma N_i V_i^2}{\Sigma N_i}$
Substituting the values of $N_i$ and $V_i$ into the formula, we get
$v_{rms}=\sqrt\frac{2(1)^2+4(2)^2+6(3)^2+8(4)^2+2(5)^2}{2+4+6+8+2}$
$v_{rms}=3.4\frac{cm}{s}$
