Answer:
The heat transfer is 29.75 kJ
Explanation:
The process is a polytropic expansion process
General polytropic expansion process is given by PV^n = constant
Comparing PV^n = constant with PV^1.2 = constant
n = 1.2
(V2/V1)^n = P1/P2
(V2/0.02)^1.2 = 8/2
V2/0.02 = 4^(1/1.2)
V2 = 0.02 × 3.2 = 0.064 m^3
W = (P2V2 - P1V1)/1-n
P1 = 8 bar = 8×100 = 800 kPa
P2 = 2 bar = 2×100 = 200 kPa
V1 = 0.02 m^3
V2 = 0.064 m^3
1 - n = 1 - 1.2 = -0.2
W = (200×0.064 - 800×0.02)/-0.2 = -3.2/-0.2 = 16 kJ
∆U = 55 kJ/kg × 0.25 kg = 13.75 kJ
Heat transfer (Q) = ∆U + W = 13.75 + 16 = 29.75 kJ
Answer:
b) Cohesive wear.
Explanation:
The question has some engineering subjects as Fatigue Mechanical, surface engineering, bearings design and material engineering.
According the definition of cohesive wear is the damage, gradual deformation of material at solid surfaces.
clean the tubes and fins with a high-pressure jet of air or mechanical scrubbing
ensure that the condenser fans are operating properly
Answer:
A retaining of a wall is a protective structure, first and foremost.
Explanation:
Its main aim is to provide functional support for keeping soil in place. It acts as a wall to keep the soil on one side and the rest of the landscape area on the other, providing a platform for a garden to be created.