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:
All of the above
Explanation:
The correct answer is option E (All of the above)
All the options are alternative source of energy.
The option given are not the traditional way (energy production from coal) of extracting energy as the loss of natural resources does not take place in these source of energy.
energy extracted from wind, solar light , hydrogen ,etc are the source of energy the alternative source of production of energy because do not exploit the natural resources, reduce the carbon emission and energy produced by them is clean energy.
Answer:
The hollow cylinder rolled up the inclined plane by 1.91 m
Explanation:
From the principle of conservation of mechanical energy, total kinetic energy = total potential energy
The total energy at the bottom of the inclined plane = total energy at the top of the inclined plane.
moment of inertia, I, of a hollow cylinder = ¹/₂mr²
substitute for I in the equation above;
given;
v₁ = 5.0 m/s
vf = 0
g = 9.8 m/s²
Therefore, the hollow cylinder rolled up the inclined plane by 1.91 m
The train is accelerating meaning there is a change in the velocity so the speed is either increasing or decreasing depending. The bicycle is travelling at a constant velocity meaning it is travelling at a constant speed.
1 Kilojoule [kJ] = 737.562 149 277 27 Foot pound force [ftlbf]
