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ser-zykov [4K]
1 year ago
12

6–23 an automobile engine consumes fuel at a rate of 22 l/h and delivers 55 kw of power to the wheels. if the fuel has a heating

value of 44,000 kj/kg and a density of 0.8 g/cm3, determine the efficiency of this engine. answer: 25.6 percent
Physics
1 answer:
Anna007 [38]1 year ago
8 0

Explanation & answer:

Given:

Fuel consumption, C = 22 L/h

Specific gravity = 0.8

output power, P  =  55 kW

heating value, H = 44,000 kJ/kg

Solution:

Calculate energy intake

E = C*P*H

= (22 L/h) / (3600 s/h) * (1000 mL/L) * (0.8 g/mL) * (44000 kJ/kg)

= (22/3600)*1000*0.8*44000 j/s

= 215111.1 j/s

Calculate output power

P = 55 kW

= 55000 j/s

Efficiency

= output / input

= P/E

=55000 / 215111.1

= 0.2557

= 25.6% to 1 decimal place.

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You are sitting in your car at rest at a traffic light with a bicyclist at rest next to you in the adjoining bicycle lane. As so
grigory [225]

Answer:

Explanation:

Time duration during which acceleration exists in  bicycle =

23 / 12 = 1.91 s

Time duration during which acceleration exists in car

= 47 / 8 = 5.875 s

Distance covered by bicycle during acceleration ( t = 1.91 s )

= 1/2 x 12 x (1.91)²

= 21.88 mi

Distance covered by car during this time ( t = 1.91 s )

= 1/2 x 8 x (1.91)²

7.64 mi ,

velocity of car after 1.91 s

= 8 x 1.91 = 15.28 mi/h

Let after time 1.91 , time taken by them to meet each other be t

Total distance covered by cycle = total distance covered by car

21.88 + 23 t = 7.64 + 15.28t + 4 t²

21.88 = 7.64 - 7.72t +4 t²

4 t² -7.72 t -14.24 = 0

t = 2.83 s

Total time taken

= 2.83 + 1.91

= 4.74 s

So after 4.74 s they will meet each other.

b ) Maximum distance occurs when velocity of both of them becomes equal .

Velocity after 1.91 s of bicycle

12 x 1.91 = 23 mi/h

Velocity after 1.91 s of car

8 x 1.91 = 15.28 mi/h . Let after time t , the velocity of car becomes 23

15.28 + 8t = 23

t = .965 s

So after time .965 s , car has velocity equal to that of bicycle.

The bicycle will travel a distance of

= 21.88 + .965 x 23 = 44.075 mi

car will travel a distance of

7.64 + 15.28 x .965 + .5 x 8 x .965²

= 7.64 + 14.75 + 3.72

= 26.11 mi

Distance between car and bicycle

= 44.075 - 26.11 = 17.965 mi

= 17.965 x 1760

= 31618.4 ft.

5 0
1 year ago
Coffee is poured at a uniform rate at 20 cm3 / s into a cup whose inside is shaped like a truncated cone. if the upper and lower
Vladimir [108]

Let the cup is filled to height h after some time

now the total volume of coffee filled in the cup is given as

\frac{2}{y} = \frac{4}{6+y}

2y = 6 + y

y = 6 cm

now volume of the coffee will be

V = \frac{1}{3}\pi r^2(y + 6) - \frac{1}{3}\pi 2^2 (6)

here we know that

\frac{r}{y+6} = \frac{2}{6}

r = \frac{y+6}{3}

V = \frac{1}{3}\pi (\frac{y+6}{3})^2(y+6) - \frac{1}{3}\pi 2^2(6)

now we know that volume flow rate is given as

Q = \frac{dV}{dt}

20 cm^3/s = \frac{1}{3}\pi (\frac{1}{9})(3(y+6)^2)\frac{dy}{dt}

20 \times 9 = \pi (y + 6)^2 v

here y = 3 cm

180 = \pi (9)^2 v

v = 0.71 cm/s

so water will rise up with speed 0.71 cm/s


5 0
2 years ago
Irrigation channels that require regular flow monitoring are often equipped with electromagnetic flowmeters in which the magneti
sveta [45]

Answer:

A) B = 9.425 × 10^(-5) T

B) North direction

Explanation:

A) We are given;

Current in coil; I = 4.5 A

Number of turns; N = 100 turns

Radius;R = diameter/2 = 6/2 = 3 m

Formula for the magnetic field at the center of the coil is given by;

B = (μ_o•N•I)/2R

Where μ_o is a constant = 4π × 10^(-7) H/m

Thus;

B = (4π × 10^(-7) × 100 × 4.5)/(2 × 3)

B = 9.425 × 10^(-5) T

B) The direction of the force on a positive ion in water can be gotten by the application of flemmings right hand rule.

From flemmings right hand rule, we know that;

- The thumb indicates the direction of the motion of the force which is in the north direction.

- The Index finger indicates the direction of the magnetic field which is in the east direction

- The middle finger indicates the direction of magnetic field which is downwards in the west direction.

Therefore, the direction of the force as seen from flemmings right hand rule is in the north direction

3 0
1 year ago
An ideal gas at temperature t0 is slowly compressed at constant pressure of 2 atm from a volume of 10 liters to a volume of 2 li
Sati [7]
<span>Answer: 1600 J

Explanation:

1) Data:

a) ideal gas: ⇒ pV = nRT and work = ∫ pdV
b) slowly compressed ⇒ constant temperature and not heat exchange
c) pressure: p =  2 atm
d) intitial volume: Vi = 10 liters
e) final volumen: Vf = 2 liters.
f) then the volume of the gas is held constant ⇒ not work in this stage.
g) calculate the work done on the gas: W = ?

2) Equation

W = ∫pdV

3) Solution:

Since p = constant,  W = p ∫dV = p ΔV = p (Vf - Vi)

p = 2 atm × 1.0 ×10⁵ Pa / atm = 200.000 Pa

Vi = 10 liter ×  0.001 m³ ./ liter = 0.01 m³

Vf = 2 liter × 0.001 m³ / liter = 0.002 m³

W = 200.000 Pa × (0.002 m³ - 0.01m³) = - 1.600 J.

The negative sign means the work is done over the system.

That is all the work in the system because at the second stage the volume is held constant.
</span>
8 0
2 years ago
Why wheat flour is usually passed near a magnet before being packed?
densk [106]
Becasue steel particles may contaminate the flour.
8 0
2 years ago
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