Explanation:
Step1
Absolute pressure is the pressure above zero level of the pressure. Absolute pressure is considering atmospheric pressure in it. Absolute pressure is always positive. There is no negative absolute pressure.
The expression for absolute pressure is given as follows:

Here,
is absolute pressure,
is gauge pressure and
is atmospheric pressure.
Step2
Gauge pressure is the pressure that measure above atmospheric pressure. It is not considering atmospheric pressure. It can be negative called vacuum or negative gauge pressure. Gauge pressure used to simplify the pressure equation for fluid analysis.
Solution :


Using the data table for refrigerant-134a at P = 120 psia



∴ 
For pressure, P = 20 psia





Change in temperature, 


Now we find the quality,



The final energy,



Change in internal energy

= 38.09297-40.5485
= -2.4556
Only put ciilant into ur radiator when the engine is cool (D)
Answer:
9500 kJ; 9000 Btu
Explanation:
Data:
m = 100 lb
T₁ = 25 °C
T₂ = 75 °C
Calculations:
1. Energy in kilojoules
ΔT = 75 °C - 25 °C = 50 °C = 50 K

2. Energy in British thermal units
