R circuit (pretty simple) need checked - full working - please

[pat666]

R circuit (pretty simple) need checked - full working - please!

Homework Statement

see attachment

Homework Equations

P=IV
P_loss=I^2 R
V=IR

The Attempt at a Solution

ok
36=I^2*12

I_{_12Ω}=√3 A
V=20.8V
That is the same for the 3 resistors in parallel (I hope)
so I_18Ω=1.15A
I_36Ω=0.577A
the sum of these will give me the current through the unknown resistor
I_unknown=3.46A
net voltage = 60
60=V_unknown + 20.8
V_unknown=39.2V
V=IR
R=11.3Ω

can someone please check this - wouldn't ask if I dint need it.

 

[rl.bhat]

Your answer is correct.

 

[pat666]

sweet, thanks rl.bhat , you don't happen to know where I can get these from do you https://www.physicsforums.com/showthread.php?p=2806831#post2806831 ?

 

[pat666]

Sorry, I forgot the second half of the question,

P_loss=I^2 R
P=〖3.46〗^2*((1/12+1/18+1/36)^(-1)+11.3)
P_loss=207.6W
This seems big to me, could you please check that too.

 

[rl.bhat]

Sorry, I forgot the second half of the question,

P_loss=I^2 R
P=〖3.46〗^2*((1/12+1/18+1/36)^(-1)+11.3)
P_loss=207.6W
This seems big to me, could you please check that too.

your answer is correct.