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Roman55 [17]
3 years ago
5

What does the atomic number tell us about an atom of a certain element?

Physics
1 answer:
Setler79 [48]3 years ago
4 0
It tells us the number of protons that are present in the nucleus, the positively charged region of that atom.
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Select all that apply.
sattari [20]

Answer: The temperature and the number of molecules must remain constant for the law to apply.

Explanation:

6 0
3 years ago
How strong an electric field is needed to accelerate electrons in an X-ray tube from rest to one-tenth the speed of light in a d
Bond [772]

Answer:

E= 50.1*10³ N/C

Explanation:

Assuming no other forces acting on the electron, if the acceleration is constant, we can use the following kinematic equation in order to find the magnitude of the acceleration:

vf^{2} -vo^{2}  = 2*a*x

We know that v₀ = 0 (it starts from rest),  that vf = 0.1*c, and that x = 0.051 m, so we can solve for a, as follows:

a = \frac{vf^{2}}{2*x} = \frac{(3e7 m/s)^{2} }{2*0.051m} =8.8e15 m/s2

According to Newton's 2nd Law, this acceleration must be produced by a net force, acting on the electron.

Assuming no other forces present, this force must be due to the electric field, and by definition of electric field, is as follows:

F = q*E (1)

In this case, q=e= 1.6*10⁻19 C

But this force, can be expressed in this way, according Newton's 2nd Law:

F = m*a (2) ,

where m= me = 9.1*10⁻³¹ kg, and a = 8.8*10¹⁵ m/s², as we have just found out.

From (1) and (2), we can solve for E, as  follows:

E=\frac{me*a}{e} =\frac{(9.1e-31 kg)*(8.8e15m/s2)}{1.6e-19C} = 50.1e3 N/C

⇒ E = 50.1*10³ N/C

3 0
4 years ago
Can somebody help please !<br><br> a. -8.3 m/s<br> b.-4.2 m/s<br> c.-0.12 m/s<br> d. 0 m/s
Gnom [1K]
The answer is a
the \: answer \: is \: a.
4 0
4 years ago
After a long night of cramming for a test, your college roommate hits his head forcefully against the wall of your room in despa
sweet [91]

Answer:

See the answer below

Explanation:

Newton's third law states that for every action, there will always be an opposing reaction of equal magnitude to the action.

<em>Hence, the wall will exert an equal opposing force to the head and the roommate will feel this opposing force as pains and/or headache. </em>

3 0
3 years ago
At a certain instant, a rotating turbine wheel of radius RR has angular speed ωω (measured in rad/srad/s). What must be the magn
jonny [76]

Answer:

Explanation:

The magnitude of the acceleration makes an angle of 30° with the tangential velocity.

Resolving the acceleration to tangential and radial acceleration

at = aCos30 = √3a/2

ar = aSin30 = ½a

a = 2•ar

Then, the tangential acceleration is the linear acceleration, so the relationship between the tangential acceleration and angular acceleration is given as:

at = Rα

Then, α = at/R

since at = √3a/2

Then, α = √3 at/2R, equation 1

The radial acceleration is given as

ar = ω²R

Note that, at² + ar² = a²

at = √(a²-ar²)

Back to equation 1

α = √3 at/2R

α = √3√(a²-ar²)/2R

α = √3√(a²-(w²R)²)/2R

α = √3(a²-w⁴R²) / 2R

Also, a = 2•ar = 2w²R

Then,

α = √3((2w²R)²-w⁴R²) / 2R

α = √3(4w⁴R²-w⁴R²) / 2R

α = √3(3w⁴R²) / 2R

α = √9w⁴R² / 2R

α = 3w²R / 2R

α = 3w²/2

7 0
3 years ago
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