4 years ago

According to the periodic table, the average atomic mass of helium is

Physics

1 answer:

vfiekz [6]4 years ago

8 0

Helium has an atomic mass of 4.00 atomic mass units.

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Why is a frame of reference important for describing<br> motion?

stepladder [879]

Answer:

the frame of reference requires deciding where the object's initial position is and which direction will be considered positive.

Explanation:

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3 years ago

A 5.0 A electric current passes through an aluminum wire of 4.0~\times~10^{-6}~m^2 cross-sectional area. Aluminum has one free e

Serhud [2]

Answer: The electron number density (the number of electrons per unit volume) in the wire is $6.0 \times 10^{28} m^{-3}$ .

Explanation:

Given: Current = 5.0 A

Area = $4.0 \times 10^{-6} m^{2}$

Density = 2.7 $g/cm^{3}$ , Molar mass = 27 g

The electron density is calculated as follows.

$n = \frac{density}{mass per atom}\\= \frac{\rho}{\frac{M}{N_{A}}}\\$

where,

$\rho$ = density

M = molar mass

$N_{A}$ = Avogadro's number

Substitute the values into above formula as follows.

$n = \frac{\rho \times N_{A}}{M}\\= \frac{2.7 g/cm^{3} \times 6.02 \times 10^{23}/mol}{27 g/mol}\\= \frac{16.254 \times 10^{23}}{27} cm^{3}\\= 0.602 \times 10^{23} \times \frac{10^{6} cm^{3}}{1 m^{3}}\\= 6.0 \times 10^{28} m^{-3}$

Thus, we can conclude that the electron number density (the number of electrons per unit volume) in the wire is $6.0 \times 10^{28} m^{-3}$ .

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3 years ago

Does knowing the origin of velocity help you understand the difference between speed and velocity?

Natasha2012 [34]

In my opinion yes it does help

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3 years ago

I can use everything on my body to advance the ball but what?

ddd [48]

The answer would be hands! hope this helps

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3 years ago

What is the force acting on the object?(g=10m/s^2)

Vera_Pavlovna [14]

Answer:w=mxg

2x10 =20 N

Explanation:force acting downwards is mg mass into gravitional feild

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4 years ago