Answer:
D.) Transfer input energy from the power source throughout the machine.
Explanation:
Since the complex abnormalities of energy efficiency is depicted by the autonomy within self-operating machines, the correct answer is D.
Answer:
a) 4.7 kΩ, +/- 5%
b) 2.0 MΩ, +/- 20%
Explanation:
a) If the resistor has the following combination of color bands:
1) Yellow = 1st digit = 4
2) Violet = 2nd digit = 7
3) Red = multiplier = 10e2
4) Gold = tolerance = +/- 5%
this means that the resistor has 4700 Ω (or 4.7 kΩ), with 5% tolerance.
b) Repeating the process for the following combination of color bands:
1) Red = 1st digit = 2
2) Black = 2nd digit = 0
3) Green = multiplier = 10e5
4) Nothing = tolerance = +/- 20%
This combination represents to a resistor of 2*10⁶ Ω (or 2.0 MΩ), with +/- 20% tolerance.
Answer:
h = 375 KW/m^2K
Explanation:
Given:
Thermo-couple distances: L_1 = 10 mm , L_2 = 20 mm
steel thermal conductivity k = 15 W / mK
Thermo-couple temperature measurements: T_1 = 50 C , T_2 = 40 C
Air Temp T_∞ = 100 C
Assuming there are no other energy sources, energy balance equation is:
E_in = E_out
q"_cond = q"_conv
Since, its a case 1-D steady state conduction, the total heat transfer rate can be found from Fourier's Law for surfaces 1 and 2
q"_cond = k * (T_1 - T_2) / (L_2 - L_1) = 15 * (50 - 40) / (0.02 - 0.01)
=15KW/m^2
Assuming SS is solid, temperature at the surface exposed to air will be 60 C since its gradient is linear in the case of conduction, and there are two temperatures given in the problem. Convection coefficient can be found from Newton's Law of cooling:
q"_conv = h * ( T_∞ - T_s ) ----> h = q"_conv / ( T_∞ - T_s )
h = 15000 W / (100 - 60 ) C = 375 KW/m^2K
Answer:
0.08kg/s
Explanation:
For this problem you must use 2 equations, the first is the continuity equation that indicates that all the mass flows that enter is equal to those that leave the system, there you have the first equation.
The second equation is obtained using the first law of thermodynamics that indicates that all the energies that enter a system are the same that come out, you must take into account the heat flows, work and mass flows of each state, as well as their enthalpies found with the temperature.
finally you use the two previous equations to make a system and find the mass flows
I attached procedure
