Answer:
Thickness of Styrofoam insulation is 0.02741 m.
Explanation:
Given that,
Height = 0.25 m
Depth = 0.5 m
Power = 400 W
Temperature = 33°C
We need to calculate the area of Styrofoam
Using formula of area

Put the value into the formula


Inner surface temperature of freezer

Outer surface temperature of freezer

We need to calculate the thickness of Styrofoam insulation
Using Fourier law,


Put the value into the formula


Hence, Thickness of Styrofoam insulation is 0.02741 m.
Answer:

Explanation:
v = Velocity of the breeze = 4 m/s
w = Width of the valley = 5000 m
h = Height of the valley = 1000 m
Volumetric flow rate is given by

= Mass flow rate of pollutant = 25 g/s = 
Concentration is given by

The steady state concentration of pollutants in the valley, is
.
Answer:

Explanation:
As we know that train is initially moving with the speed

now we know that

now the final speed of the train when it crossed the crossing


now we can use kinematics here



Now the time to cross that junction is given as



Answer:
Technician A is right.
Explanation:
Given that,
Voltage of circuit, V = 12 volt
Current in the circuit, I = 3 A
Technician A says the electric power in this circuit is 36 watts. Technician B says the electric power in this circuit is 4 watts. We need to say that which technician is correct.
The power of any circuit is given by :


P = 36 watts
So, technician A is right. Hence, this is the required solution.