In the context of mechanical systems, what does the term efficiency mean? OA the factor by which a machine multiplies a force B.
1 answer:
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Answer:
Part 1: It would be a straight line, current will be directly proportional to the voltage.
Part 2: The current would taper off and will have negligible increase after the voltage reaches a certain value. Graph attached.
Explanation:
For the first part, voltage and current have a linear relationship as dictated by the Ohm's law.
V=I*R
where V is the voltage, I is the current, and R is the resistance. As the Voltage increase, current is bound to increase too, given that the resistance remains constant.
In the second part, resistance is not constant. As an element heats up, it consumes more current because the free sea of electrons inside are moving more rapidly, disrupting the flow of charge. So, as the voltage increase, the current does increase, but so does the resistance. Leaving less room for the current to increase. This rise in temperature is shown in the graph attached, as current tapers.
Answer:
a)120C
b)29kg
Explanation:
Hello!
To solve this exercise follow the steps below
1. we will call 1 the initial state, 2 the steam that enters and 3 the final state
2. We find the quality of the initial state, dividing the mass of steam by the total mass.
3 Find the internal energy in the three states using thermodynamic tables
note:Through laboratory tests, thermodynamic tables were developed, these allow to know all the thermodynamic properties of a substance (entropy, enthalpy, pressure, specific volume, internal energy etc ..)
through prior knowledge of two other properties such as pressure and temperature.
u1=IntEnergy(Water;x=0,6(quality);P=200kPa) =1719KJ/kg
u2=IntEnergy(Water;t=350;P=5000kPa) =2808KJ/kg
u3=IntEnergy(Water;x=1;P=200kPa) =2529KJ/kg
4. use the internal energy and pressure to find the temperature in state 3, using thermodynamic tables
T3=Temperature(Water;P=200kPa;u=u3=2529KJ/kg)=120C
5. Use the first law of thermodynamics in the system, it states that the initial energy in a system must be equal to the final
m1u1+m2u2=(m1+m2)u3
where
m1=inital mass=10kg
m2=the mass of the steam that has entered.
solve for m2
(m1)(u1-u3)=(m2)(u3)-(m2)(u2)