Answer
$43.9^{\circ}C$
Work Step by Step
The rms speed is given by equation 13–9. Use kelvins to measure the temperatures.
$$\frac{v_{rms,2}}{v_{rms,1}}=1.040=\frac{\sqrt{3kT_2/m}}{\sqrt{3kT_1/m}}=\sqrt{\frac{T_2}{T_1}}$$
$$T_2=T_1(1.04)^2=(293.15K)(1.040)^2=317.07K=43.9^{\circ}C$$