Select the correct answer.
2 answers:
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Answer:
1028.1184 Ohms
Explanation:
<u>Given the following data;</u>
- Initial resistance, Ro = 976 Ohms
- Initial temperature, T1 = 0°C
- Final temperature, T2 = 89°C
Assuming the temperature coefficient of resistance for carbon at 0°C is equal to 0.0006 per degree Celsius.
To find determine its new resistance, we would use the mathematical expression for linear resistivity;
Substituting into the equation, we have;
Answer:
The correct answer is 'velocity'of liquid flowing out of an orifice is proportional to the square root of the 'height' of liquid above the center of the orifice.
Explanation:
Torricelli's theorem states that
where
is the velocity with which the fluid leaves orifice
is the head under which the flow occurs.
Thus we can compare the given options to arrive at the correct answer
Velocity is proportional to square root of head under which the flow occurs.
Answer:
The radius of a wind turbine is 691.1 ft
The power generation potential (PGP) scales with speed at the rate of 7.73 kW.s/m
Explanation:
Given;
power generation potential (PGP) = 1000 kW
Wind speed = 5 mph = 2.2352 m/s
Density of air = 0.0796 lbm/ft³ = 1.275 kg/m³
Radius of the wind turbine r = ?
Wind energy per unit mass of air, e = E/m = 0.5 v² = (0.5)(2.2352)²
Wind energy per unit mass of air = 2.517 J/kg
PGP = mass flow rate * energy per unit mass
PGP = ρ*A*V*e
r = 210.64 m = 691.1 ft
Thus, the radius of a wind turbine is 691.1 ft
PGP = CVᵃ
For best design of wind turbine Betz limit (c) is taken between (0.35 - 0.45)
Let C = 0.4
PGP = Cvᵃ
take log of both sides
ln(PGP) = a*ln(CV)
a = ln(PGP)/ln(CV)
a = ln(1000)/ln(0.4 *2.2352) = 7.73
The power generation potential (PGP) scales with speed at the rate of 7.73 kW.s/m