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Masteriza [31]
3 years ago
12

A fairly efficient steam turbine engine fired by coal is used to drive an electric generator. The generator operates between 210

0°C and 385°C.
(a) Determine the maximum possible efficiency of the engine.


Answer: 72.3 %


Formula:

e = 1 - (Tc / Th) = 1 - (Qc / Qh) = ( W / Qh)


Explanation: Unsure??


(b) The engine absorbs 1.15 105 J from the hot reservoir every second. If the actual efficiency of the engine is 40.3%, determine the mechanical power the engine delivers.


Answer: 46 kW


Explanation:

Energy absorbed by the engine (J) * actual efficiency of the engine (%) = mechanical power the engine delivers (kW)


How does 1 - (385/2100) = 72.3 % ?
What do I Plug in to make e = 72.3 %
Physics
1 answer:
Ber [7]3 years ago
5 0

Use kelvin not celsius

C + 273 = K

This will fix my problem of the equation not making sense.

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  • Velocity=108km/h

Convert to m/s

\\ \tt\longmapsto 108\times \dfrac{5}{18}

\\ \tt\longmapsto 30m/s

  • Time=30s.

\\ \tt\longmapsto Distance=Velocity\times Time

\\ \tt\longmapsto Distance=30(30)

\\ \tt\longmapsto Distance=900m

6 0
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Even when the head is held erect, as in the figure below, its center of mass is not directly over the principal point of support
alexandr1967 [171]

We are asked to determine the force required by the neck muscle in order to keep the head in equilibrium. To do that we will add the torques produced by the muscle force and the weight of the head. We will use torque in the clockwise direction to be negative, therefore, we have:

\Sigma T=r_{M\perp}(F_M)-r_{W\perp}(W)

Since we want to determine the forces when the system is at equilibrium this means that the total sum of torque is zero:

r_{M\perp}(F_M)-r_{W\perp}(W)=0

Now, we solve for the force of the muscle. First, we add the torque of the weight to both sides:

r_{M\perp}(F_M)=r_{W\perp}(W)

Now, we divide by the distance of the muscle:

(F_M)=\frac{r_{W\perp}(W)}{r_{M\perp}}

Now, we substitute the values:

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Now, we solve the operations:

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Therefore, the force exerted by the muscles is 23.53 Newtons.

Part B. To determine the force on the pivot we will add the forces we add the vertical forces:

\Sigma F_v=F_j-F_M-W

Since there is no vertical movement the sum of vertical forces is zero:

F_j-F_M-W=0

Now, we add the force of the muscle and the weight to both sides to solve for the force on the pivot:

F_j=F_M+W

Now, we plug in the values:

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8 0
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andrezito [222]

Answer:

When the air pressure in the throat and outside the body is less than the air pressure in the middle ear, barotrauma occurs.

Explanation:

Ear barotrauma is a medical condition that describes discomfort in the ear which is caused by pressure differences in the inner and outer ear drum.

Usually, the air pressure in the middle ear is the same as the air pressure in the throat and outside the body.

When we swallow, the eustachian tube opens up and air flows out of and into the middle ear, this balances the pressure. But if the eustachian tube is blocked, the air pressure in the throat and outer body become different from the air pressure in the middle ear.

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