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4 years ago

How many neutrons does element X have if its atomic number is 23 and its mass number is 90?

Physics

2 answers:

givi [52]4 years ago

4 0

Answer:

Explanation:

- The atomic number (Z) of an atom is equal to the number of protons in the nucleus

- The mass number (A) of an atom is equal to the sum of protons and neutrons in the nucleus

Therefore, calling p the number of protons and n the number of neutrons, for element X we have:

Z = p = 23

A = p + n = 90

Substituting p=23 into the second equation, we find the number of neutrons:

n = 90 - p = 90 - 23 = 67

Zina [86]4 years ago

4 0

<h2>Answer:</h2>

<u>The number of neutrons is </u><u>67</u>

<h2>Explanation:</h2>

As we know that the atomic number is the number of protons. If we subtract the atomic number from the mass number, we can actually find the number of neutrons.

Number of neutrons = Mass number - atomic number

Neutrons = 90 - 23 = 67

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Someone help me haha;(

Nikitich [7]

Answer: vf = 51 m/s

d = 112 m

Explanation: Solution attached:

To find vf we use acceleration equation:

a = vf - vi / t

Derive to find vf

vf = at + vi

Substitute the values

vf = 3.5 m/s² ( 8.0 s) + 23 m/s

= 51 m/s

To solve for distance we use

d = (∆v)² / 2a

= (51 m/s - 23 m/s )² / 2 ( 3.5 m/s²)

= (28 m/s)² / 7 m/s²

= 784 m/s / 7 m/s²

= 112 m

6 0

3 years ago

The velocity of a particle is given by v=20t² - 100t + 50, where v is in meters per second and t is in seconds. Evaluate the vel

allochka39001 [22]

Explanation:

It is given that,

The velocity of a particle is given by :

$v=20t^2-100t+50$

Where

v is in m/s and t is in seconds

Let a is the acceleration of the object at time t. So,

$a=\dfrac{dv}{dt}$

$a=\dfrac{d(20t^2-100t+50)}{dt}$

$a=40t-100$

When a = 0

$40t-100=0$

t = 2.5 s

a is zero at t = 2.5 s. Velocity, $v=20(2.5)^2-100(2.5)+50$

v = -75 m/s

Since, $v=\dfrac{ds}{dt}$ , s is the distance travelled

$s=\int\limits{vdt}$

$s=\int\limits{(20t^2-100t+50)dt}$

$s=\dfrac{20t^3}{3}-50t^2+50t$

At t = 2.5 s, $s=\dfrac{20(2.5)^3}{3}-50(2.5)^2+50(2.5)$

s = −83.34 m

Hence, this is the required solution.

5 0

3 years ago

Read 2 more answers

A 2000 Hz siren and a civil defense official are both at rest with respect to the ground. What frequency does the official hear

astra-53 [7]

Answer:

a) $f_1 = 2070.6 Hz$

b) $f_2 = 1929.4 Hz$

Explanation:

Apparent frequency of the siren is given as

$f = \frac{v_{rel}}{\lambda}$

as we know that the wavelength will remain the same as it is having originally

sowe know

$\lambda = \frac{340}{2000}$

$\lambda = 0.17 m$

a) Now when wind is blowing from source to official

so we have

$v_{rel} = 340 + 12 = 352 m/s$

so we have

$f_1 = \frac{352}{0.17}$

$f_1 = 2070.6 Hz$

b) Now when wind is from official to source

so we have

$v_{rel} = 340 - 12 = 328 m/s$

so we have

$f_2 = \frac{328}{0.17}$

$f_2 = 1929.4 Hz$

4 0

4 years ago

An electronics technician wishes to construct a parallelplate capacitor using rutile (k=100) as the dielectric. The area of the

My name is Ann [436]

Given k=100, Area if plate A = 1.00 cm2

$= 1 x (10-2)2 m^{2}$

Thickness of rutile $ds = t = 1.00 mm$

$= 1 x 10-3 cm$

Without any dielectric medium capacitance of a parallel plate capacitor is c = oAd

When a dielectric is placed between capacitors plates then capacitance c1 = KoAd

Here $d = t = 1 x 10-1 cm$ , $o = 8.854 x 10-12 c^{2} m^{-2} N$

Now $c1 = 100 X 8.859 X 10^{-12} X 1 X (10-2)^{21} X 10^{-2}$

$= 8.859 X 10-1910-3= 8.85 X 10-11 F= 8.85 X 10-12 F$

$C1 = 88.5 X 10-12 F$

$C1 = 88.5 PF$

Correct Option: A

What purposes serve parallel plate capacitors?

The following are some uses for parallel plate capacitors:

This kind of capacitor is utilized in rechargeable energy systems such as batteries.
These capacitors are used in systems for dynamic digital memory.
Such capacitors are used in pulsed laser and radar circuits.

To learn more about Parallel plate capacitors, visit:

brainly.com/question/12733413

#SPJ4

5 0

2 years ago

Why do sound waves move faster through the ground than through the air? A. Particles of matter are packed more loosely in the gr

Fittoniya [83]

Answer:

Explanation:

5 0

4 years ago