xkcd

9187 readers

1 users here now

A community for a webcomic of romance, sarcasm, math, and language.

founded 2 years ago

MODERATORS

[email protected]

277

xkcd #3038: Uncanceled Units (xkcd.com)

submitted 2 weeks ago* (last edited 2 weeks ago) by [email protected] to c/[email protected]

75 comments fedilink hide all child comments

Edit: Alt Text: Speed limit c arcminutes^2 per steradian.

you are viewing a single comment's thread
view the rest of the comments

[–] [email protected] 20 points 2 weeks ago (1 children)

No, it's because watts are joules per second, so kWh are (energy / time) * time. Cancelling the units would be expressing the energy directly in joules.

[–] [email protected] 12 points 2 weeks ago (2 children)

But the XKCD mentions kWh/day specifically, in theory the times can cancel out, leaving you with kW

But instantaneous and average kW are very different, and it would take more time to describe that distinction than to use kWh/day.

[–] [email protected] 3 points 2 weeks ago

My freezer was labeled in max watts, kwh/day, and kwh/year. Because the cumulative watts over time is what I pay for my power bill. That way it's a simple multiplication that tells me how much having that freezer would cost.

[–] [email protected] 1 points 1 week ago

Ok that's fair, I kinda glossed over that part. Both are valid interpretations, I think.