Answer:
c. expanded polyurethane
Explanation:
Thermal performance of a building fabric is measured in terms of heat loss and is expressed as U-value or R-value. U-value is the rate of heat transferred through a structure divided by the difference in temperature across the structure with a unit of measurement of W/m²K.You can calculate the U-value of a by getting the reciprocal of the sum of thermal resistances , R, making the building material.
If you have the value of R, then U=1/R
Material size R U
plywood 1" 1.25 0.8
Poured concrete 2" 0.99 1.010
Expanded polyurethane 1" 6.5 0.1538
Asbestos shingles 1" 0.03 33.33
The material with lowest U-value is expanded polyurethane
Answer:
Step one : read the directions
Step two: complete the assignment
Explanation:
Answer:
P = 5sin(880πt)
Explanation:
We write the pressure in the form P = Asin2πft where A = amplitude of pressure, f = frequency of vibration and t = time.
Now, striking the middle-A tuning fork with a force that produces a maximum pressure of 5 pascals implies A = 5 Pa.
Also, the frequency of vibration is 440 hertz. So, f = 440Hz
Thus, P = Asin2πft
P = 5sin2π(440)t
P = 5sin(880πt)
