A direct current
this is a current that only flows in one direction
Your "weight" is the name you give to that gravitational force.
So your question actually says:
"Your weight just got three times stronger !
What happens to your weight ?"
(a) 0.249 (24.9 %)
The maximum efficiency of a heat engine is given by
![\eta = 1-\frac{T_C}{T_H}](https://tex.z-dn.net/?f=%5Ceta%20%3D%201-%5Cfrac%7BT_C%7D%7BT_H%7D)
where
Tc is the low-temperature reservoir
Th is the high-temperature reservoir
For the engine in this problem,
![T_C = 270^{\circ}C+273=543 K](https://tex.z-dn.net/?f=T_C%20%3D%20270%5E%7B%5Ccirc%7DC%2B273%3D543%20K)
![T_H = 450^{\circ}C+273=723 K](https://tex.z-dn.net/?f=T_H%20%3D%20450%5E%7B%5Ccirc%7DC%2B273%3D723%20K)
Therefore the maximum efficiency is
![\eta = 1-\frac{T_C}{T_H}=1-\frac{543}{723}=0.249](https://tex.z-dn.net/?f=%5Ceta%20%3D%201-%5Cfrac%7BT_C%7D%7BT_H%7D%3D1-%5Cfrac%7B543%7D%7B723%7D%3D0.249)
(b-c) 0.221 (22.1 %)
The second steam engine operates using the exhaust of the first. So we have:
is the high-temperature reservoir
is the low-temperature reservoir
If we apply again the formula of the efficiency
![\eta = 1-\frac{T_C}{T_H}](https://tex.z-dn.net/?f=%5Ceta%20%3D%201-%5Cfrac%7BT_C%7D%7BT_H%7D)
The maximum efficiency of the second engine is
![\eta = 1-\frac{T_C}{T_H}=1-\frac{423}{543}=0.221](https://tex.z-dn.net/?f=%5Ceta%20%3D%201-%5Cfrac%7BT_C%7D%7BT_H%7D%3D1-%5Cfrac%7B423%7D%7B543%7D%3D0.221)
Heat
gained in a system can be calculated by multiplying the given mass to the
specific heat capacity of the substance and the temperature difference. It is
expressed as follows:<span>
Heat = mC(T2-T1)
345.2 = 89.5(C)(305 - 285)
C = 0.1928 </span>J/g•K