Given Information:
Inlet Temperature of hot air= Th₁ = 450K
Exit Temperature of hot air = Th₂ = 350K
Inlet Temperature of cold air = Tc₁ = 300K
Volume flow rate of hot air = vh = 0.02 m³/s
Volume flow rate of cold air = vc = 1 m³/s
Required Information:
Exit Temperature of cold air= Tc₂ = ?
Answer:
Exit Temperature of cold air = Tc₂ = 302 °C
Explanation:
In a heat exchanger, the cold air absorbs heat that is lost by the hot air,
Heat absorbed by cold air = Heat lost by hot air
Therefore, the exit temperature of the cold air is 302 °C or 575K
Note:
m = ρv
Where ρ is density of air and v is the volume flow rate and m is the mass flow rate.
cp is the specific heat capacity of air.
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Weight = (mass) x (acceleration of gravity).
When I calculate the weight of the 81.6 kg, the number I use for gravity
is 9.807 m/s². That gives a weight of 800.25 N, so I think that's where the
question got the crazy number of 81.6 kg ... whoever wrote the problem
wants the hay to weigh 800 N, and that's what I'll use for the weight.
The forces on the bale of hay are gravity: 800N downward, and the
guy on the truck with the pitchfork pulling upward on it with 850 N.
The net force on the bale is (850 - 800) = 50 N upward.
Use Newton's second law of motion: (Net force) = (mass) x (acceleration)
Divide each side by 'mass' :
Acceleration = (net force)/(mass)
On the hay wagon,
Acceleration = (50 N upward) / (81.6 kg) = <em>0.613 m/s² upward</em>