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
<span>A. Pecos Bill
</span>According to “The Cyclone,” who invented the Fourth of July is PECOS BILL
NOT:
B. Alexander Hamilton
<span>C. Sam Houston </span>
<span>D. George Washington</span>
Answer:
Electric field acting on the electron is 127500 N/C.
Explanation:
It is given that,
Mass of an electron,
Charge on electron,
Initial speed of electron, u = 0
Final speed of electron,
Distance covered, s = 2 cm = 0.02 m
We need to find the electric field required. Firstly, we will find the acceleration of the electron from third equation of motion as :
According to Newton's law, force acting on the electron is given by :
F = ma
Electric force is given by :
F = q E, E = electric field
E = 127500 N/C
So, the electric field is 127500 N/C. Hence, this is the required solution.
Explanation:
Given that,
Mass, m = 0.08 kg
Radius of the path, r = 2.7 cm = 0.027 m
The linear acceleration of a yo-yo, a = 5.7 m/s²
We need to find the tension magnitude in the string and the angular acceleration magnitude of the yo‑yo.
(a) Tension :
The net force acting on the string is :
ma=mg-T
T=m(g-a)
Putting all the values,
T = 0.08(9.8-5.7)
= 0.328 N
(b) Angular acceleration,
The relation between the angular and linear acceleration is given by :
(c) Moment of inertia :
The net torque acting on it is, , I is the moment of inertia
Also,
So,
Hence, this is the required solution.
The answer would be “B” because humans would need water, protection from radiation so we don’t melt or burn to death lol, and a gaseous atmosphere because we would need oxygen.