Answer:
B. 180 million joules
Explanation:
Apply the formula for heat transfer given as;
Q=m*c*Δt where
Q = electrical energy consumed by the heater in joules
m= mass of air in the chamber in kg
c= specific heat of air in joules per kg degrees Celsius
Δt= change in temperatures in degrees Celsius
Given in the question;
m= 1200 kg
c= 1000 J/°C /kg
Δt = 180°-30°= 150° C
Substitute values in the equation to get Q as;
Q=m*c*Δt
Q= 1200 * 1000* 150
Q= 180000000 joules
Q = 180 million joules
<u>The correct answer option is B : 180 million joules.</u>
Answer:critical stress= 20.23 MPa
Explanation:
Since there was an internal crack, we will divide the length of the internal crack by 2
Length of internal crack, a = 0.7mm,
Half length = 0.7mm/2= 0.35mm changing to meters becomes
0.35/ 1000= 0.35 x 10 ^-3m
The formulae for critical stress is calculated using
σC = (2Eγs /πa) ¹/₂
σC = critical stress=?
Given
E= Modulus of Elasticity= 225GPa =225 x 10 ^ 9 N/m²
γs= Specific surface energy = 1.0 J/m2 = 1.0 N/m
a= Half Length of crack=0.35 x 10 ^-3m
σC= (2 x 225 x 10 ^ 9 N/m² x 1.0 N/m /π x 0.35 x 10 ^-3m)¹/₂
=(4.5 x 10^11/π x 0.35 x 10 ^-3)¹/₂
=(4.0920 x10 ^14)¹/₂
σC=20.23 x10^6 N/m² = 20.23 MPa
Answer:
1). Linear and syndiotactic poly(vinyl chloride); linear and isotactic polystyrene
2). Network phenol-formaldehyde; linear and heavily crosslinked cis-isoprene
3). Linear polyethylene, lightly branched isotactic polypropylene
Explanation:
1). It is very much possible to decide for the two polymers. Here the linear as well as the syndiotactic poly(vinyl chloride) are likely to be crystallize; the side - group phenyl of the polystyrene is more bulkier than CI side group for the poly(vinyl chloride). The syndiotactic as well as the isotactic isomers are likely to crystallize equally.
2). No we cannot decide for the two polymers. Both of them are crosslinked and the network polymers may not crystallize.
3). It is a possible to decide the two polymers. The linear polyethylene is likely to crystallize.
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