GCSE Physics - I'm so lost

Okay so heres my problem. I'm doing a practice question of Specific heat capacity and how it works. I got a question like:- Electric Kettle with thermal cap = 820- Has inside 0.9KG water- Takes 9 minutes to raise temp from 19 to 100 (81 temp difference)- how much longer will it take to boil another half of the kettle?I was given the answer to the question after getting it wrong but it has confused me so much more. Mainly for this one section of working out:Total heat in 9 minutes = Q=306180 66420 = 372600372600/(9X60) = 2000 J2000J = 690WSo my issue with this answer is how did they swap J to W in the end? i can't find the values any where (this is apparently a necessary step). Also how would I know in an exam to switch it to W? Note I will not be given ANY equations in this next exam I have coming up (my memory is useless) so if there is a long equation can you try and simplify it? ThanksAny help appreciated

Reply 1

Baza2002

Let me tell you
Anyone with a similar problem
Read this too
So Watts is the measurement
Of power
'I got the power'
Joules is the measurement
Of Energy
What time is it?
9pm
But that is irrelevant
As it is not related to the pen
That you are using
Whilst finding the question confusing
And I find it amusing
Nine minutes you say?
It will pay
To convert it to seconds today
Nine times by sixty
Is five-hundred and forty
Hmm...
Power
Energy
Time.
To get the solution
We need an equation
Which you will not hear on a radio station
Power is what you need
Should I feed
You
And others too
The equation
Power is
Energy transferred
Yes, that is what you heard
Divided by time
And no,
This doesn't give you the power
To commit a crime.

Power = energy transferred/time