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2 years ago

The phase sequence of a 3-phase system for which VAN = 120 /90o V and VBN = 120 /210o V is:_______

Engineering

1 answer:

Vadim26 [7]2 years ago

4 0

Answer:

b. abc

Explanation:

The phase rotation and its sequence is order in which voltage is reached to their respective sources. The wave forms of a polyphase flow through AC source to the panel. The three phase system has two possible sequence which can be a-b-c or c-b-a. The correct answer is therefore b.

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An inventor claims to have invented a heat engine that operates between the temperatures of 627°C and 27°C with a thermal effici

Oksana_A [137]

Answer Explanation:

the efficiency of the the engine is given by=1- $\frac{T_2}{T_1}$

where T₂= lower temperature

T₁= Higher temperature

we have given efficiency =70%

lower temperature T₂=27°C=273+27=300K

higher temperature T₁=627°C=273+627=900K

efficiency=1- $\frac{T_2}{T_1}$

=1- $\frac{300}{900}$

=1-0.3333

=0.6666

=66%

66% is less than 70% so so inventor claim is wrong

3 0

2 years ago

A reservoir delivers water to a horizontal pipeline 39 long The first 15 m has a diameter of 50 mm, after which it suddenly beco

allsm [11]

Answer:

The difference of head in the level of reservoir is 0.23 m.

Explanation:

For pipe 1

$d_1=50 mm,f_1=0.0048$

For pipe 2

$d_2=75 mm,f_2=0.0058$

Q=2.8 l/s

$Q=2.8\times 10^{-3]$

We know that Q=AV

$Q=A_1V_1=A_2V_2$

$A_1=1.95\times 10^{-3}m^2$

$A_2=4.38\times 10^{-3} m^2$

$So V_2=0.63 m/s,V_1=1.43 m/s$

head loss (h)

$h=\dfrac{f_1L_1V_1^2}{2gd_1}+\dfrac{f_2L_2V_2^2}{2gd_2}+0.5\dfrac{V_1^2}{2g}$

Now putting the all values

$h=\dfrac{0.0048\times 15\times 1.43^2}{2\times 9.81\times 0.05}+\dfrac{0.0058\times 24\times 0.63^2}{2\times 9.81\times 0.075}+0.5\dfrac{1.43^2}{2\times 9.81}$

So h=0.23 m

So the difference of head in the level of reservoir is 0.23 m.

8 0

2 years ago

Match the military operation to the category of satellite that would perform it.

SOVA2 [1]

Answer:

1. Location of enemy ground troops - EARTH OBSERVING.

Using earth observing satellite imagery, the military can observe vast expanses of land and in so doing, find the location of enemy ground troops.

2. Routine reconnaissance of an unfamiliar climate - WEATHER

In other to find out more about the climate of an area, a weather satellite can be used to observe the areas and its changing weather patterns.

3. Analyze waterways in an unfamiliar location - NAVIGATION

Using navigation satellites, navigation conduits such as roads and waterways can be observed.

4. Provide warning of an attack - COMMUNICATION.

Communications satellites enable people to communicate over great distances and so can be used by the military to warn of an impending attack.

5 0

2 years ago

After replacing a vacuum booster, the brakes lock up on a road test. Technician A says there is air trapped inside the brake lin

vitfil [10]

Answer:

Technician B

Explanation:

The brakes can lockup due to the following reasons

1) Overheating break systems

2) Use of wrong brake fluid

3) Broken or damaged drum brake backing plates, rotors, or calipers

4) A defective ABS part, or a defective parking mechanism or proportioning valve

5) Brake wheel cylinders, worn off

6) Misaligned power brake booster component

5 0

2 years ago

4. A banking system provides users with several services:

VLD [36.1K]

A diagram showing a use case diagrams for these requirements is given in the image attached.

<h3>What is system Case diagram?</h3>

A use case diagram is known to be a kind of graphical illustration of a users in terms of their various possible association or interactions within any given system.

A use case diagram in banking can be used to prepare, depict and also to know all the functional requirements of the banking system.

Therefore, Give the use case specification for the banking system services and paying a bill online is given in the image attached.

Learn more about Case diagram from

brainly.com/question/12975184

#SPJ1

4 0

2 years ago