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Alenkinab [10]
3 years ago
12

The Chinese had a toy helicopter some 1000 years ago. True Or False ?

Engineering
1 answer:
Vadim26 [7]3 years ago
5 0

Answer:

f

Explanation:

for the lazy people

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What is the name for a program based on the way your brain works?
xxMikexx [17]

Answer:

KAT

Explanation:

I believe this is what ur looking for

8 0
3 years ago
Read 2 more answers
A satellite orbits the Earth every 2 hours at an average distance from the Earth's centre of 8000km. (i) What is the average ang
AlexFokin [52]

Answer:

i)ω=3600 rad/s

ii)V=7059.44 m/s

iii)F=1245.8 N

Explanation:

i)

We know that angular speed given as

\omega =\dfrac{d\theta}{dt}

We know that for one revolution

θ=2π

Given that time t= 2 hr

So

ω=θ/t

ω=2π/2 = π rad/hr

ω=3600 rad/s

ii)

Average speed V

V=\sqrt{\dfrac{GM}{R}}

Where M is the mass of earth.

R is the distance

G is the constant.

Now by putting the values

V=\sqrt{\dfrac{GM}{R}}

V=\sqrt{\dfrac{6.667\times 10^{-11}\times 5.98\times 10^{24}}{8000\times 10^3}}

V=7059.44 m/s

iii)

We know that centripetal fore given as

F=\dfrac{mV^2}{R}

Here given that m= 200 kg

R= 8000 km

so now by putting the values

F=\dfrac{mV^2}{R}

F=\dfrac{200\times 7059.44^2}{8000\times 10^3}

F=1245.8 N

3 0
3 years ago
What is an advantage of a nuclear-fission reactor?.
Kobotan [32]

Answer:

Nuclear fission is almost 8,000 times more efficient than traditional fossil fuels at producing energy. That's a lot of energy packed into a small space. Nuclear energy is more efficient, which means it uses less fuel to power the plant and produces less waste.


advantages:
-produces no polluting gases
-does not contribute to global warming
-very low fuel costs
-Low fuel quantity reduces mining and transportation effects on environment
-High technology research required benefits other industries
-Power station has very long lifetime

Disadvantages:
-Waste is radioactive and safe disposal is very difficult and expensive
-Local thermal pollution from wastewater affects marine life
-Large-scale accidents can be catastrophic
-Public perception of nuclear power is negative
-Costs of building and safely decommissioning are very high
-Cannot react quickly to changes in electricity demand

4 0
2 years ago
What is flow energy? Do fluids at rest possess any flow energy?
anzhelika [568]

Answer:

Flow energy is defined as, flow energy is the energy needed to push fluids into control volume and it is the amount of work done required to push the entire fluid. It is also known as flow work. Flow energy is not the fundamental quantities like potential and kinetic energy.

Fluid at state of rest do not possess any flow energy. It is mostly converted into internal energy as, rising in the fluid temperature.

8 0
3 years ago
1. Which of the following will cause a spark knock?
zlopas [31]

Answer:

I couldn't find options for your question online, but I can give you an explanation so you can choose the correct option.

Explanation:

A spark knock is a form of unpredictable behavior that occurs in combustion, that is, in the chemical reaction that occurs between oxygen and an oxidizable material. Such combustion is usually manifested by incandescence or flame.

The spark knock is a detonation that occurs when there is a lot of pressure in the fuel.

<u>Some situations in which this can happen are: </u>

  • Engine overloaded.
  • Maximum pressure in the cylinders.
  • Engine overheated.
  • Overheated air.
  • Long and excessive engine ignition timing.
  • Spark plug at high temperatures.
5 0
3 years ago
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