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3 years ago

TE

1 answer:

7 0

This would be answer choice D: all of the above. Low back pain can be classified by duration as acute (pain lasting less than 6 weeks), sub-chronic (6 to 12 weeks), or chronic (more than 12 weeks).

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A power washer is being used to clean the siding of a house. Water enters at 20 C, 1 atm, with a velocity of 0.2 m/s .A jet of w

BabaBlast [244]

A power washer is being used to clean the siding of a house. Water at the rate of 0.1 kg/s enters at 20°c and 1 atm, with the velocity 0.2m/s. The jet of water exits at 23°c, 1 atm with a velocity 20m/s at an elevation of 5m. At steady state, the magnitude of the heat transfer rate from power unit to the surroundings is 10% of the power input. Determine the power input to the motor in kW.

Answer:

Net power of 1.2 KW is being extracted

Explanation:

We are given;

Mass flow rate; m' = 0.1kg/s

Inlet temperature; T1 = 20°C = 293K

Inlet pressure; P1 = 1 atm = 10^(5) pa

Inlet velocity; v1 = 0.2 m/s

Exit Pressure; P2 = 1 atm = 10^(5) pa

Exit Temperature; T2 = 1 atm = 296K

Exit velocity; V2 = 20m/s

Change in elevation; h = Z2 - Z1 = 5m

We are told that the magnitude of the heat transfer rate from the power unit to the surroundings is 10% of the power input.

Thus;

Q = -0.1W

From Bernoulli equation;

Q - W = ∆Potential energy + ∆Kinetic energy + ∆Pressure energy

Where;

∆Potential energy = mg(z2 - z1)

∆Kinetic energy = ½m(v2² - v1²)

∆Pressure energy = mc_p(T2 - T1)

Thus;

-0.1W - W = [m'g(z2 - z1)] + [½m'(v2² - v1²)] + [m'c_p(T2 - T1)]

Where C_p is specific heat capacity of water = 4200 J/Kg.k

Plugging in the relevant values, we have;

-1.1W = (0.1 × 9.81 × 5) + (½ × 0.1(20² - 0.2²)) + (0.1 × 4200 × (296 - 293))

-1.1W = 4.905 + 19.998 + 1260

-1.1W = 1284.903

W = -1284.903/1.1

W ≈ -1168 J/s ≈ -1.2 KW

The negative sign means that work is extracted from the system.

7 0

3 years ago

Write the following statements as Prolog clauses, in the order given: If it is raining or snowing, then there is precipitation.

Anika [276]

Answer:

a. See Explanation Below

b. No

Explanation:

Interpreting the statements line by line.

First, the prolog clauses need to be initialised, as follows:

:- dynamic freezing/0, precipitation/0, snowing/0, raining/0.

If it is raining or snowing, then there is precipitation.

The statement is splited in two.

1st, if it is raining then there is precipitation

2nd, if it is raining, then there is precipitation.

So, both statements are given as:

precipitation :- raining.

precipitation :- snowing.

If it is freezing and there is precipitation, then it is snowing.

This is a conditional statement that checks if it is freezing AND there's is precipitation.

If true, then it is snowing.

The above statement is given as:

snowing :- freezing, precipitation.

If it is not freezing and there is precipitation, then it is raining.

This is a conditional statement that checks if it is not freezing AND there's is precipitation.

If true, then it is raining.

The not clause is represented as \+

The above statement is the given as:

raining :- \+ freezing, precipitation.

It is snowing.

This is represented as follows

snowing.

So, the full prolog clause is as follows

:- dynamic freezing/0, precipitation/0, snowing/0, raining/0.

precipitation :- raining.

precipitation :- snowing.

snowing :- freezing, precipitation.

raining :- \+ freezing, precipitation.

snowing.

b. What answer does Prolog give to the following queries:

Is it freezing

Reason;

All of the conditions above point to raining or snowing; none points to freezing.

Hence, it is no.

8 0

3 years ago

How much extra water does a 21.5 ft, 175-lb concrete canoe displace compared to an ultra-lightweight 38-lb Kevlar canoe of the s

pantera1 [17]

Answer:

The volume of the extra water is $2.195 ft^{3}$

Solution:

As per the question:

Mass of the canoe, $m_{c} = 175 lb + w$

Height of the canoe, h = 21.5 ft

Mass of the kevlar canoe, $m_{Kc} = 38 lb + w$

Now, we know that, bouyant force equals the weight of the fluid displaced:

Now,

$V\rho g = mg$

$V = \frac{m}{\rho}$ (1)

where

V = volume

$\rho = 62.41 lb/ft^{3}$ = density

m = mass

Now, for the canoe,

Using eqn (1):

$V_{c} = \frac{m_{c} + w}{\rho}$

$V_{c} = \frac{175 + w}{62.41}$

Similarly, for Kevlar canoe:

$V_{Kc} = \frac{38 + w}{62.41}$

Now, for the excess volume:

V = $V_{c} - V_{Kc}$

V = $\frac{175 + w}{62.41} - \frac{38 + w}{62.41} = 2.195 ft^{3}$

8 0

3 years ago

What historical event allowed both aerospace fields to make enormous strides forward?

Lostsunrise [7]

Answer:

The world wars. Especially world War II

Explanation:

The world wars were the single most notable events that led to the leap in development of the aircraft from a simple apparatus capable of flight to a sophisticated flight machine. Airplane production was at its maximum during these periods (especially world war II) and has never seen that capacity of production again since. Countries focused on research that could add even the slightest enhancements to their aircraft in order to for it to surpass that of other countries.

6 0

3 years ago

What engine does the mercedes 500e have

Strike441 [17]

Answer:

5.0 m119

Explanation:

It has the 5.o m119 v8 engine which produced 322 bhp.

5 0

3 years ago