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:
Mass and volume.
Explanation:
The equation for density is always mass divided by volume. To determine the density of a fluid, you would need to find its volume and its mass.
Answer:
Explanation:
Given
Resistor A has length 
and Resistor B has Length 
and Resistance is given by
Considering 
and A to be constant thus
because 
(a)When they are connected in series
As the current in series is same and power is 
therefore 
as R is greater for second resistor
(b)if they are connected in Parallel
In Parallel connection Voltage is same
resistance of 2 is greater than 1 thus Power delivered by 1 is greater than 2
A body of mass m has weight
F = GMm/r²
on the surface of the Earth, where G is the universal gravitational constant, M is the mass of the Earth, and r is it's radius.
If the weight is to be halved, then we have
1/2 F = 1/2 GMm/r² = (1/√2)² GMm/r² = GMm/(√2 r²)
so the distance between the body and the planet's center needs to be
√2 × 6.4 × 10⁶ m ≈ 9.1 × 10⁶ m
