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Arturiano [62]
3 years ago
11

For a heat pump, COP<1. a) True b) False

Engineering
1 answer:
frez [133]3 years ago
3 0

Answer:

B

Explanation:

its B trust me i dont feel like explaining

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These are the most widely used tools and most often abuse tool​
Mars2501 [29]
Where is the picture in this problem? How am I supposed to answer if I can’t see any footage taken from this problem.
4 0
3 years ago
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A step-up transformer has 20 primary turns and 400 secondary turns. If the primary current is 30 A, what is the secondary curren
-BARSIC- [3]
150
A
Explanation:
V
s
V
p
=
N
s
N
p

(
1
)
N
refers to the number of turns
V
is voltage
s
and
p
refer to the secondary and primary coil.
From the conservation of energy we get:
V
p
I
p
=
V
s
I
s

(
2
)
From
(
1
)
:
V
s
V
p
=
900
00
3
00
=
300
∴
V
s
=
300
V
p
Substituting for
V
s
into
(
2
)
⇒
V
p
I
p
=
300
V
p
×
0.5
∴
I
p
=
150
A
Seems a big current.
3 0
3 years ago
P9.28 A large vacuum tank, held at 60 kPa absolute, sucks sea- level standard air through a converging nozzle whose throat diame
eimsori [14]

Answer:

a)  m=0.17kg/s

b)  Ma=0.89

Explanation:

From the question we are told that:

Pressure P=60kPa

Diameter d=3cm

Generally at sea level

T_0=288k\\\\\rho_0=1.225kg/m^3\\\\P_0=101350Pa\\\\r=1.4

Generally the Power series equation for Mach number is mathematically given by

\frac{p_0}{p}=(1+\frac{r-1}{2}Ma^2)^{\frac{r}{r-1}}

\frac{101350}{60*10^3}=(1+\frac{1.4-1}{2}Ma^2)^{\frac{1.4}{1.4-1}}

Ma=0.89

Therefore

Mass flow rate

\frac{\rho_0}{\rho}=(1+\frac{1.4-1}{2}(0.89)^2)^{\frac{1.4}{1.4-1}}

\frac{1.225}{\rho}=(1+\frac{1.4-1}{2}(0.89)^2)^{\frac{1.4}{1.4-1}}

\rho=0.848kg/m^3

Generally the equation for Velocity at throat is mathematically given by

V=Ma(r*T_0\sqrt{T_e})

Where

T_e=\frac{P_e}{R\rho}\\\\T_e=\frac{60*10^6}{288*0.842\rho}

T_e=248

Therefore

V=0.89(1.4*288\sqrt{248})\\\\V=284

Generally the equation for Mass flow rate is mathematically given by

m=\rho*A*V

m=0.84*\frac{\pi}{4}*3*10^{-2}*284

m=0.17kg/s

6 0
2 years ago
Before finishing and installing a shelved cabinet you just constructed, you need to check the
Greeley [361]

Answer:

Carpenter's square

Explanation:

The most common hand tool used to measure or set angles with its application extending to setting angles of roofs and rafters. Another name of a Carpenter's square is a framing square.

Other hand tools that are used to measure angles are;

  • The combination square that allows a user to set both 90°  and 45° angles
  • A Bevel that allows users to set any angle they like.
  • A Protractor that resembles a bevel but its marks are marked in an arc.
  • An electromagnetic angle finder which gives a reading according to the measure of the arms adjusted by the user.
7 0
3 years ago
Select the correct answer.
boyakko [2]
I think the answer is b
6 0
3 years ago
Read 2 more answers
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