Identify an object in your house that contains a physical system and list three questions you could use to define the system
1 answer:
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Answer:
The rate of work output = -396.17 kJ/s
Explanation:
Here we have the given parameters
Initial temperature, T₁ = 355°C = 628.15 K
Initial pressure, P₁ = 350 kPa
h₁ = 763.088 kJ/kg
s₁ = 4.287 kJ/(kg·K)
Assuming an isentropic system, from tables, we look for the saturation temperature of saturated air at 4.287 kJ/(kg·K) which is approximately
h₂ = 79.572 kJ/kg
The saturation temperature at the given
T₂ = 79°C
The rate of work output =
×
×(T₂ - T₁)
Where;
= The specific heat of air at constant pressure = 0.7177 kJ/(kg·K)
= The mass flow rate = 2.0 kg/s
Substituting the values, we have;
= 2.0 × 0.7177 × (79 - 355) = -396.17 kJ/s
= -396.17 kJ/s
Answer:
C) 43,2°C
Explanation:
<em>Sensible heat</em> is the amount of thermal energy that is required to change the temperature of an object, the equation for calculating the heat change is given by:
Q=msΔT
where:
- Q, heat that has been absorbed or realeased by the substance [J]
- m, mass of the substance [g]
- s, specific heat capacity [J/g°C]
- ΔT, changes in the substance temperature [°C]
To solve the problem, we clear ΔT of the equation and then replace our data:
Q=890 [J],
m=16,6 [g],
s=2,74 [J/g°C]
Q=msΔT.......................ΔT=Q/ms
Δ°C
As:
ΔT=Tfinal-Tinitial
Tfinal=ΔT+Tinitial
Tfinal=21,7+21,5=43,2°C
The final temperature of the ethanol is 43,2°C.