Really? "7.2 watt-hours in 15 seconds in watts" doesn't "just work" in google. Can you post a one-liner that does the same calculation in google or other site?
That calculation is not the same one I'm asking for. It's not watts per hour as you've written -- it's actually watt-hours (watt * hour). The answer is also incorrect -- it's not 0.03 watts -- it's 1730 watts. So my request still stands -- show me a one-liner for my original calculation. It's not as simple as you think. ;)
Of course, many other tools can do this almost-trivial unit conversion for you. Unless you have forgotten how many seconds are in a minute or how many foos are in a kilofoo, you should be able to do this in your head...
Now, if you wanted to integrate that...