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4 years ago

15

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

2 answers:

givi [52]4 years ago

4 0

Answer:

67

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.

So

Number of neutrons = Mass number - atomic number

Neutrons = 90 - 23 = 67

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the maximum normal force a pilot can withstand is about eight times his weight. What is the maximum radius of curvature that a j

neonofarm [45]

Complete Question

the maximum force a pilot can stand is about seven times his weight. what is the minimum radius of curvature that a jet plane's pilot, pulling out of a vertical dive, can tolerate at a speed of 250m/s?

Answer:

The value is $r = \frac{250^2 }{6 * 9.8 }$

Explanation:

From the question we are told that

The weight of the pilot is $W = mg$

The maximum force a pilot can withstand is $F_{max} = 7 W = 7 (mg)$

The speed is $v = 250 \ m/s$

Generally the centripetal force acting on the pilot is equal to the net force acting on the pilot i.e

$F_c = F_{max} - mg$

Here N is the normal force acting on the pilot

Now

$F_c = \frac{m v^2 }{r}$

So

$\frac{m v^2 }{r} = 7(mg) - mg$

=> $r = \frac{v^2 }{6g}$

=> $r = \frac{250^2 }{6 * 9.8 }$

=> $r = 1063 \ m$

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3 years ago

Describe the direction in which each object will accelerate. If the object won't accelerate, write "no acceleration." Explain wh

fgiga [73]

Answer:

No acceleration. All of the forces are acting equally on the paper air plane therfore It isn't going to move any where.

5 0

3 years ago

Which characteristic gives the most information about what kind of element an atom is ?

Butoxors [25]

Answer:

The atomic number

Explanation:

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4 years ago

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Mohs scale is used in describing which characteristic? luster toughness hardness crystal form

Lady_Fox [76]

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3 years ago

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A thin stream of water flows smoothly from a faucet and falls straight down. At one point the water is flowing at a speed of v1

MrRa [10]

Answer:

The vertical distance between these two points is 12.28 cm.

Explanation:

Given that,

Speed of water = 1.23 m/s

Diameter at lower point d'= 0.787 d

We need to calculate the speed of water

Using continuity equation

$A_{1}v_{1}=A_{2}v_{2}$

$\dfrac{\pi\times d^2}{4}v_{1}=\dfrac{\pi\times d'^2}{4}v_{2}$

$v_{2}=v_{1}\times(\dfrac{d}{d'})^2$

Put the value into the formula

$v_{2}=1.23\times(\dfrac{d}{0.787d})^2$

$v_{2}=1.98\ m/s$

We need to calculate the vertical distance h between these two points

Using Bernoulli theorem

$P_{1}+\dfrac{1}{2}\rho v_{1}^2+\rho gh_{1}=P_{2}+\dfrac{1}{2}\rho v_{2}^2+\rho gh_{2}$

Here, P₁ = P₂ = atmosphere pressure is same because both end is open

$\dfrac{1}{2}\rho(v_{2}^2-v_{1}^2)=\rho\times g(h_{1}-h_{2})$

$(v_{2}^2-v_{1}^2)=2g(h_{1}-h_{2})$

$2g\times\Delta h=(v_{2}^2-v_{1}^2)$

$\Delta h=\dfrac{1.98^2-1.23^2}{2\times9.8}$

$\Delta h=12.28\ cm$

Hence, The vertical distance between these two points is 12.28 cm.

6 0

4 years ago