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Sladkaya [172]
3 years ago
6

Which represents an endothermic reaction? wood burning in a fire splitting a gas molecule changing frost to water vapor TNT expl

oding
Physics
2 answers:
brilliants [131]3 years ago
4 0

Answer:

B

Explanation:

Splitting a gas molecule

Elis [28]3 years ago
3 0

Answer:

splitting a gas molecule

Explanation:

Endothermic reactions can be regarded as chemical reactions whereby there is absorbing of heat energy by the reactant from the surroundings when forming the products. Cooling effect is created because the reaction will lower the surrounding temperature after it must have absorbed heat. In endothermic reaction, the standard enthalpy change ΔH⚬ is positive. For instance when gas molecules is splitter heat energy is absorbed.

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6- A metal block measures 10 cm x 2 cm x 2 cm. what is its volume? how many blocks each
zalisa [80]
You need 5 blocks of the smaller object to contain the same amount of volume of the bigger object

3 0
4 years ago
The critical angle for a light ray travelling from a ruby into ethyl alcohol is 50.6 degrees celsius. Determine the index of ref
stepan [7]
In order to answer this question, I realized that I needed to know the index
of refraction for ruby, so I went and looked it up.  It's  1.762 to 1.770 .

I started trying to remember how to use this number and the critical angle
to find the index of refraction of the other medium.  That's when I saw the
absurd unit "degrees celsius" for the critical angle, and I got discouraged.
But I perked up very quickly, when I realized that I'm still on the "index of
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It's  1.36  .


8 0
3 years ago
A wind turbine is rotating at 15 rpm under steady winds flowing through the turbine at a rate of 42,000 kg/s. The tip velocity o
zzz [600]

Answer:

a) 5.22 m/s

b) 31.4 %

Explanation:

f = rotating speed = 15 rpm = 15/60 =0.25 rps

m = Mass flow rate of air = 42000 kg/s

v = Tip velocity = 250 km/h = 250/3.6 = 69.44 m/s

W = Work output = 180 kW

A = Swept area of wind turbine

r = Radius of wind turbine

η = Efficiency

r=\frac{v}{2\pi f}\\\Rightarrow r=\frac{250\div 3.6}{2\pi 0.25}=\frac{250}{1.8\pi}

A=\pi r^2\\\Rightarrow A=\pi\left(\frac{250}{1.8\pi}\right)^2\\\Rightarrow A=\left(\frac{250}{1.8}\right)^2\frac{1}{\pi}

m=\rho V\\\Rightarrow m=\rho vA\\\Rightarrow v=\frac{m}{\rho A}\\\Rightarrow v=\frac{42000}{1.31 \left(\frac{250}{1.8}\right)^2\frac{1}{\pi}}\\\Rightarrow v=5.22\ m/s

∴ The average velocity of the air is 5.22 m/s

E=m\frac{v^2}{2}=42000\frac{5.22^2}{2}\\\Rightarrow E=572538.92

\eta=\frac{W}{E}=\frac{180000}{572538.92}\\\Rightarrow \eta =0.314

∴ Conversion efficiency of the turbine is 0.314 or 31.4 %

7 0
3 years ago
Read 2 more answers
g 2. In a laboratory experiment on standing waves a string 3.0 ft long is attached to the prong of an electrically driven tuning
abruzzese [7]

Answer:

The tension in string will be "3.62 N".

Explanation:

The given values are:

Length of string:

l = 3 ft

or,

 = 0.9144 m

frequency,

f = 60 Hz

Weight,

= 0.096 lb

or,

= 0.0435 kgm/s²

Now,

The mass will be:

= \frac{0.0435}{9.8}

= 0.0044 \ kg

As we know,

⇒  \lambda=\frac{2L}{n}

On substituting the values, we get

⇒     =\frac{2\times 0.9144}{4}

⇒     =0.4572 \ m

or,

⇒  v=f \lambda

⇒      =0.4572\times 60

⇒      =27.432 \ m/s

Now,

⇒  v=\sqrt{\frac{T}{\mu} }

or,

⇒  T=\frac{m}{l}\times v^2

On putting the above given values, we get

⇒      =\frac{0.0044}{0.9144}\times (27.432)^2

⇒      =\frac{752.51\times 0.0044}{0.9144}

⇒      =3.62 \ N

7 0
3 years ago
A flat loop of wire consisting of a single turn of cross-sectional area 7.80 cm2 is perpendicular to a magnetic field that incre
mihalych1998 [28]

Answer:

Explanation:

Area of crossection, A = 7.80 cm²

Initial magnetic field, B = 0.5 T

Final magnetic field, B' = 3.3 T

Time, t = 1 s

resistance of the coil, R = 1.2 ohm

The induced emf is given by

e=\frac{d\phi}{dt}=A\frac{B' - B}{t}

where, Ф is the rate of change of magnetic flux.

e = 7.80 x 10^-4 x (3.3 - 0.5) / 1

e = 2.184 mV

i = e/R

i = 2.184/1.2

i = 1.82 mA

4 0
3 years ago
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