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vovangra [49]
3 years ago
12

A fan that is switched on for 1 minute uses 500 W usefully but also wastes 300 W through the emission of sound and heat. What's

the efficiency of the fan?
Physics
1 answer:
koban [17]3 years ago
6 0

Explanation:

Efficiency is defined as the ratio between the useful output over the total amount consumed. E = \frac{useful}{total}

The fan does 500W of useful work while wasting 300 W. The total power consumption is 800 W (500 + 300).

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Why are different constellations<br> of stars seen during different<br> seasons?
slamgirl [31]
Actually, they're not.  There's a group of stars and constellations arranged
around the pole of the sky that's visible at any time of any dark, clear night,
all year around.  And any star or constellation in the rest of the sky is visible
for roughly 11 out of every 12 months ... at SOME time of the night. 

Constellations appear to change drastically from one season to the next,
and even from one month to the next, only if you do your stargazing around
the same time every night.

Why does the night sky change at various times of the year ?  Here's how to
think about it:

The Earth spins once a day. You spin along with the Earth, and your clock is
built to follow the sun . "Noon" is the time when the sun is directly over your
head, and "Midnight" is the time when the sun is directly beneath your feet.

Let's say that you go out and look at the stars tonight at midnight, when you're
facing directly away from the sun.

In 6 months from now, when you and the Earth are halfway around on the other
side of the sun, where are those same stars ?  Now they're straight in the
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THAT's why stars and constellations appear to be in a different part of the sky,
at the same time of night on different dates.
5 0
3 years ago
Read 2 more answers
An engine is used to lift a beam weighing 9,800 N up to 145 m. How much work must the engine do to lift this beam? How much work
Arturiano [62]

Explanation:

Given that,

Weight of the engine used to lift a beam, W = 9800 N

Distance, d = 145 m

Work done by the engine to lift the beam is given by :

W = F d

W=9800\ N\times 145\ m\\\\W=1421000\ J\\\\W=1421\ kJ

Let W' is the work must be done to lift it 290 m. It is given by :

W'=9800\ N\times 290\ m\\\\W'=2842000\ J\\\\W'=2842\ kJ

Hence, this is the required solution.

5 0
3 years ago
Assume an axon has an internal diameter of 1μm and a myelin sheath 1μm thick. The internal specific resistance is 100 Ω cm. For
SpyIntel [72]

Answer:

1.27\times 10^{12}\Omega/m

Explanation:

We are given that

Diameter=d=\mu m

Thickness=1\mu m

Radius=r=\frac{d}{2}=\frac{1}{2}\mu m=0.5\times 10^{-6} m

Using 1\mu m=10^{-6} m

Dielectric constant=8

Resistance =R=2\times 10^5\Omega cm^2

Internal specific resistance=r=100 ohm cm=100\times \frac{1}{100}\Omega-m=1\Omega m

Using 1 m=100 cm

Internal resistance per unit length=\frac{r}{A}=\frac{1}{\pi r^2}=\frac{1}{3.14\times (0.5\times 10^{-6})^2}=1.27\times 10^{12}\Omega/m

Using \pi=3.14

Internal resistance per unit length=1.27\times 10^{12}\Omega/m

8 0
3 years ago
The square loop shown in the figure moves into a 0.80T magnetic field at a constant speed of 10m/s. The loop has a resistance of
PolarNik [594]
The question ask to find and calculate the induced current in the loop as a function time and the best answer would be that the induced current in the loop is 0.08 amperes. I hope you are satisfied with my answer and feel free to ask for more if you have clarifications and further questions
7 0
3 years ago
Read 2 more answers
On earth, what is a child’s mass if the force of gravity on the child’s body is 100 N
ikadub [295]

Answer: 10.2 kg if g = 9.8, 10 if g = 10.

Explanation:

Weight or the "force of gravity" on a person is simply defined by the equation: F = ma. In this case, the acceleration is g, which is 9.8 but can be rounded up to 10. Based on this, we have:

F = mg

100 = m*9.8

m = 10.2(or 10 if we set g to 10).

4 0
3 years ago
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