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4 years ago

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A machine is supplied energy at a rate of 4,000 W and does useful work at a rate of 3,760 W. What is the efficiency of the machi

ne

1 answer:

Dmitry_Shevchenko [17]4 years ago

8 0

= (3,760 joule/sec) / (4,000 joule/sec)

= 3,760 / 4,000 = 0.94 = 94%

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How are science and technology the same

Ilia_Sergeevich [38]

Answer:

Science is the study of the natural world by collecting data through a systematic process called the scientific method. And technology is where we apply science to create devices that can solve problems and do tasks. Technology is literally the application of science

Explanation:

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3 years ago

Water flows through a water hose at a rate of Q1 = 860 cm3/s, the diameter of the hose is d1 = 1.85 cm. A nozzle is attached to

Snowcat [4.5K]

Answer:

a) A1 = $\frac{\pi (d1)^{2} }{4}$

b) A1 = 2.688 cm $^{2}$

c) Q1 = A1 x v1

d) v1 = 3.1994 m/s

e) A2 = $\frac{A1 X v1}{v2}$

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Explanation:

a) Area = $\pi r^{2}$

r = $\frac{d}{2}$

thus,

area = $\pi (\frac{d}{2})^{2}$

A1 = $\frac{\pi (d1)^{2} }{4}[/tex]b) d1 = 1.85 cmsubstituting in the above equation,A1 = [tex]\frac{\pi (d1)^{2} }{4}$

A1 = $\frac{\pi (1.85)^{2} }{4}$

A1 = 2.688 cm $^{2}$

c) Flow rate = Area x velocity ( refer brainly.com/question/13997998)

Q1 = A1 x v1

d) From the above equation,

v1 = $\frac{Q1}{A1}$ = $\frac{860}{2.688}$ = 319.94 cm/s = 3.1994 m/s

e) Since the flow rate Q1 is constant throughout the hose, Av is a constant.

i.e. A1 x v1 = A2 x v2

thus,

A2 = $\frac{A1 X v1}{v2}$

f) v2 = 10.8 m/s.

substituting the values in the above equation,

A2 = $\frac{2.688 X 3.1994}{10.8}$ = 0.7963cm $^{2}$

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4 years ago

Why evaporation are called surface phenomenon?

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The water formed on the surface of the water evaporation loss (evaporation), consisting of plant transpiration water loss (transpiration) is called. Soil near the plant and the resulting water loss is called by evapotranspiration.

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4 years ago

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A rotating wheel requires 5 s to rotate 38 revolutions. Its angular velocity at end of time interval 5-s is 79 rad/s. What is th

Lera25 [3.4K]

"Rotating wheel" is meant to indcate that the wheel is already rotating at the start. Denote the initial angular velocity by <em>ω₀</em>. Then the angular displacement <em>θ</em> at time <em>t</em> is

<em>θ</em> = <em>ω₀t</em> + 1/2 <em>αt</em> ²

while the angular velocity <em>ω</em> is

<em>ω</em> = <em>ω₀</em> + <em>αt</em>

<em />

It takes 5 s for the wheel to rotate 38 times, or turn a total of (2<em>π</em> rad/rev) (38 rev) = 76<em>π</em> rad, as well as to reach an angular velocity of 79 rad/s, so that

76<em>π</em> rad = <em>ω₀</em> (5 s) + 1/2 <em>α</em> (5 s)²

79 rad/s = <em>ω₀</em> + <em>α</em> (5 s)

Solve the second equation for <em>ω₀</em> and substitute into the first equation, then solve for <em>α</em> :

<em>ω₀</em> = 79 rad/s - <em>α</em> (5 s)

==> 76<em>π</em> rad = (79 rad/s - <em>α</em> (5 s)) (5 s) + 1/2 <em>α</em> (5 s)²

==> 76<em>π</em> rad = (79 rad/s) (5 s) - 1/2 <em>α</em> (5 s)²

==> 1/2 <em>α</em> (5 s)² = (79 rad/s) (5 s) - 76<em>π</em> rad

==> <em>α</em> = ((79 rad/s) (5 s) - 76<em>π</em> rad) / (1/2 (5 s)²)

==> <em>α</em> ≈ 12.5 rad/s²

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3 years ago

What are some examples of how we use science in or daily lives?

mamaluj [8]

Answer: Science is involved in cooking, eating, breathing, driving, playing, etc. The fabric we wear, the brush and paste we use, the shampoo, the talcum powder, the oil we apply, everything is the consequence of advancement of science. Life is unimaginable without all this, as it has become a necessity.

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3 years ago

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