Answer:
f_D = =3.24 N/m
Explanation:
data given
properties of air

k = 0.0288 W/m.K
WE KNOW THAT
Reynold's number is given as


= 1.941 *10^4
drag coffecient is given as

solving for f_D


Drag coffecient for smooth circular cylinder is 1.1
therefore Drag force is

f_D = =3.24 N/m
The job that the fan is designed and built to do is to convert the electrical energy it uses into the kinetic (motion) energy of moving air.
I can't really guarantee that it accomplishes that with MOST of the electrical energy it uses, because I don't know how efficient your fan is. For example, if it's a really old fan, and one blade has the end broken off, and a lot of dust and mosquitoes have gotten into the motor, and it shakes and vibrates and makes a lot of noise when it's running, then it's converting a lot of the electrical energy into thermal energy (it gets hot when it runs) and some into sound energy too.
If you can live without the word "most" in the question, then we can assume that the fan is well designed and running like a top, and the answer is definitely choice-B .
Answer: Heat current through the insulator=196W
Electric power= 196W
Explanation: Given: Kglass = 0.040W/m
Temperature of inside glassTi=175°C
Temperature of outside glass To= 35°C
Area=1.4m^2 , L= 4×10^-2
Heat current(H)= K ×A× (Ti - To)/L
Substituting the values into the equation
H = 0.04 × K × 1.4 ×(175-35)/4×10^-2
H= 196W.
The electric power = Heat current =196W
The electric power is the magnitude of heat current
The work done by a system on a different body is equal to the product of the force exerted and the distance that the body has move in parallel to the force exerted. In this item, we have to determine first the distance and multiply it with the given force equal to 750N.