Answer:
a) 3.242
b) 1291.178 KJ
c) 3.59 cents
Explanation:
a) First all the temperature units should be in Kelvin. -30°C + 273.15 = 243.15K and 45°C + 273.15 = 318.15K. Coefficient of performance for refrigerator is COP = TL/(TH-TL) where TL is Lower Temperature and TH is the Higher Temperature. COP = 243.15/(318.15-243.15) = 3.242
b) COP = Cooling Effect/Work Input. Cooling Effect (or Desired Output) is 4186 kJ.
So Work Input = Cooling Effect/COP = 4186KJ/3.242= 1291.178 KJ
c) 3.6 MJ (3600kJ) is for 10 cents, using ratio for cost: energy used
![\frac{10}{3600 kJ} =\frac{x}{1291.178kJ}](https://tex.z-dn.net/?f=%5Cfrac%7B10%7D%7B3600%20kJ%7D%20%3D%5Cfrac%7Bx%7D%7B1291.178kJ%7D)
3.59 cents
Answer:
is greatest
Explanation:
Given:
![S(r)=ar^2(r_{o}-r)](https://tex.z-dn.net/?f=S%28r%29%3Dar%5E2%28r_%7Bo%7D-r%29)
![\frac{ds}{dr}=2ar(r_{o}-r)+ar^2(-1)](https://tex.z-dn.net/?f=%5Cfrac%7Bds%7D%7Bdr%7D%3D2ar%28r_%7Bo%7D-r%29%2Bar%5E2%28-1%29)
![\frac{ds}{dr}=2ar_{o}-2ar^2-ar^2](https://tex.z-dn.net/?f=%5Cfrac%7Bds%7D%7Bdr%7D%3D2ar_%7Bo%7D-2ar%5E2-ar%5E2)
![\frac{ds}{dr}=2ar_{o}-3ar^2](https://tex.z-dn.net/?f=%5Cfrac%7Bds%7D%7Bdr%7D%3D2ar_%7Bo%7D-3ar%5E2)
Substitute
, so
![2ar_{o}-3ar^2=0](https://tex.z-dn.net/?f=2ar_%7Bo%7D-3ar%5E2%3D0)
Then, get the common value from the equation.
![ra(2r_{o}-3r) = 0](https://tex.z-dn.net/?f=ra%282r_%7Bo%7D-3r%29%20%3D%200)
![\bf{r=0}\\r=\frac{2r_{o}}{3}](https://tex.z-dn.net/?f=%5Cbf%7Br%3D0%7D%5C%5Cr%3D%5Cfrac%7B2r_%7Bo%7D%7D%7B3%7D)
![(\frac{d^2s}{dr^2})_{r=0}=2ar_{o}-6ar](https://tex.z-dn.net/?f=%28%5Cfrac%7Bd%5E2s%7D%7Bdr%5E2%7D%29_%7Br%3D0%7D%3D2ar_%7Bo%7D-6ar)
![(\frac{d^2s}{dr^2})_{r=0}=2ar_{o} >0\;and, \\(\frac{d^2s}{dr^2})_{r}=\frac{2r_o}{3}](https://tex.z-dn.net/?f=%28%5Cfrac%7Bd%5E2s%7D%7Bdr%5E2%7D%29_%7Br%3D0%7D%3D2ar_%7Bo%7D%20%3E0%5C%3Band%2C%20%5C%5C%28%5Cfrac%7Bd%5E2s%7D%7Bdr%5E2%7D%29_%7Br%7D%3D%5Cfrac%7B2r_o%7D%7B3%7D%20%3C0)
So, the speed of the air is greatest.
![\bf{r=\frac{2r_o}{3}}\;is\;greatest](https://tex.z-dn.net/?f=%5Cbf%7Br%3D%5Cfrac%7B2r_o%7D%7B3%7D%7D%5C%3Bis%5C%3Bgreatest)
Answer:
.
= 2574.08
Explanation:
given data
magnitude V1 = 80
magnitude V2 = 50
angle a = -37°
solution
= 80 k
= 50 cos{37} i - 50sin{37} k
so that here
.
is
.
= 80 k . ( 50 cos{37} i - 50sin{37} k )
.
= 80 k . ( 38.270 i + 32.176 k )
.
= 2574.08
There are many things spinach is high in. Here are a couple: Spinach is high in fiber, vitamins and in magnesium, manganese, iron and folate, it also has calcium and potassium.
Answer:
If you were to look for a cut on the palmar surface of a dog's leg then you should look at the back area of the front leg below the carpus.
Explanation: