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katrin [286]
3 years ago
5

How do I get number of atoms?

Physics
1 answer:
Zina [86]3 years ago
4 0
To calculate the number of atoms in a sample, divide its weight in grams by the amu atomic mass from the periodic table, then multiply the result by Avogadro's number: 6.02 x 10^23.
You might be interested in
Air at 80 kPa and 127 °C enters an adiabatic diffuser steadily at a rate of 6000 kg/h and leaves at 100 kPa. The velocity of the
Vinil7 [7]

Answer:

a) The exit temperature is 430 K

b) The inlet and exit areas are 0.0096 m² and 0.051 m²

Explanation:

a) Given:

T₁ = 127°C = 400 K

At 400 K, h₁ = 400.98 kJ/kg (ideal gas properties table)

The energy equation is:

q-w=h_{2} -h_{1} +\frac{V_{2}^{2}-V_{1}^{2}    }{2} +delta-p

For a diffuser, w = Δp = 0

The diffuser is adiabatic, q = 0

Replacing:

0-0=h_{2} -h_{1} +\frac{V_{2}^{2}-V_{1}^{2}    }{2} +0

Where

V₁ = 250 m/s

V₂ = 40 m/s

Replacing:

0-0=h_{2} -400x10^{3}  +\frac{40^{2}-250^{2}      }{2} +0\\h_{2} =431430 J/kg=431.43kJ/kg

Using tables, at 431.43 kJ/kg the temperature is 430 K

b) The inlet area is:

m=\frac{P_{1} }{RT_{1} } A_{1} V_{1} \\\frac{6000}{3600} =\frac{80}{0.287*400} A_{1} *250\\A_{1} =0.0096m^{2}

The exit area is:

m=\frac{P_{2} }{RT_{2} } A_{2} V_{2} \\\frac{6000}{3600} =\frac{100}{0.287*430} A_{2} *40\\A_{2} =0.051m^{2}

6 0
3 years ago
Yagnasree M.,........................ <br> ​
borishaifa [10]

Answer:

uh huh???

Explanation:

8 0
3 years ago
A uniform disk has a mass of 3.7 kg and a radius of 0.40 m. The disk is mounted on frictionless bearings and is used as a turnta
nevsk [136]

Answer:

1.25 kgm²/sec

Explanation:

Disk inertia, Jd =

Jd = 1/2 * 3.7 * 0.40² = 0.2960 kgm²

Disk angular speed =

ωd = 0.1047 * 30 = 3.1416 rad/sec

Hollow cylinder inertia =

Jc = 3.7 * 0.40² = 0.592 kgm²

Initial Kinetic Energy of the disk

Ekd = 1/2 * Jd * ωd²

Ekd = 0.148 * 9.87

Ekd = 1.4607 joule

Ekd = (Jc + 1/2*Jd) * ω²

Final angular speed =

ω² = Ekd/(Jc+1/2*Jd)

ω² = 1.4607/(0.592+0.148)

ω² = 1.4607/0.74

ω² = 1.974

ω = √1.974

ω = 1.405 rad/sec

Final angular momentum =

L = (Jd+Jc) * ω

L = 0.888 * 1.405

L = 1.25 kgm²/sec

4 0
4 years ago
A local fast food company sells a 16-oz soft drink. To determine if the soft drinks served contain &lt; the advertised 16 oz, a
kakasveta [241]

Answer:

Hypothesis testing.

Explanation:

In the given problem it has been claimed that the mean of the population amount is less than 16  oz. for this claim, a test is conducted using the sample of size  20  and it was concluded that there is no evidence to say that mean amount is less than  the claimed amount.  i.e 16 oz

Hence, it is an example of the hypothesis testing.

6 0
3 years ago
The froghopper Philaenus spumarius is supposedly the best jumper in the animal kingdom. To start a jump, this insect can acceler
Kay [80]

Answer:

Part a)

v_f = 4 m/s

Part b)

t = 0.001 s

Part c)

d = 0.815 m

Explanation:

Part a)

As we know that initially the grass hopper is at rest at the ground position

Now the acceleration is given as

a = 4000 m/s^2

distance of the legs that it stretched is given as

s = 2.0 mm

so we have

v_f^2 - v_i^2 = 2 a d

v_f^2 - 0 = 2(4000)(0.002)

v_f = 4 m/s

Part b)

time taken to reach this speed is given as

v_f - v_i = at

4 - 0 = 4000 t

t = 0.001 s

Part c)

as the grass hopper reach the maximum height its final speed would be zero

so we will have

v_f^2 - v_i^2 = 2 a d

0 - 4^2 = 2(-9.81) d

d = 0.815 m

5 0
3 years ago
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