8.96 g/cm^3 * 50 mm * ((25/2) mm)^2 * pi * 0.39 (kJ/(kg K)) * 30K / 8W in seconds

Uh oh! Wolfram|Alpha doesn't run without JavaScript.

Please enable JavaScript. If you don't know how, you can find instructionshere.Once you've done that, refresh this page to start using Wolfram|Alpha.