What does the II next to an element mean?

Answer:

electrons move around nucleus in specific regions

We have that the correct statement that summarizes atoms over time will be

The discovery of new evidence resulted in changes to the atomic theory.

Option B

Generally

The Image shows that in the early 1800 the knowledge of atom was limited and it increased over time and by 1920 it had gone through a 4 stages of modifications to the atomic model

Therefore the correct statement that summarizes atoms over time will be

The discovery of new evidence resulted in changes to the atomic theory

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Answer:

Explanation:

Its resistor

Answer:

-7.5

Explanation:

edge 2021

The kinetic energy is calculated by work done, The work done is equal to the change in kinetic energy when the object is at rest.

Kinetic energy (KE) is calculated using the formula:

KE = (1/2) × mass × velocity²

However, if you don't have the velocity value, it is not possible to calculate the kinetic energy accurately. Velocity is a crucial component in determining kinetic energy because it quantifies the object's speed and direction of motion.

But there is a special case when the object is at rest the change in velocity is equal to the work done.

Therefore, The kinetic energy is calculated by work done, The work done is equal to the change in kinetic energy when the object is at rest.

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Answer:

The term "aerobic" refers to the body's ability to provide energy through the use of oxygen.  The term anaerobic refers to the body's ability to provide energy without the use of oxygen.

An example of an aerobic exercise is swimming. An example of an anaerobic exercise is sprinting.

Explanation:

Answer:

An example of an aerobic exercise is swimming. An example of an anaerobic exercise is sprinting.

Explanation:

Answer:

Explanation:

Explanation: total displacement =3√2m. and total distance covered=14m. I hope this is right and helps u.

Answer:65.28

Explanation:

A long string has a standing wave with 2 loops at a frequency. The speed of the waves in the string is 65.28 m/s

The frequency is the number of cycles completed per second.

Given the length of the string l = is 1.70 m, no of loops n =2, frequency of wave f =38.4 Hz, then the speed of the waves is

f = nv /2l

Substitute the following values, we get

v = 38.4 x 2 x 1.70 / 2

v =65.28 m/s

Thus, the speed of the waves in the string is 65.28 m/s.

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Answer:

B

Explanation:

atoms with equal or similar electronegativity form covalent bonds in which the valence electrons are shared between the two atom

During the formation of a chemical bond, the expected result is that the electrons will complete a noble gas configuration in both atoms. Hence, option (C) is correct.

The given problem is based on the concepts and fundamentals of chemical bonds. The chemical bonds between the two atomic species is formed by sharing the electrons.

Thus, we can conclude that during the formation of a chemical bond, the expected result is that the electrons will complete a noble gas configuration in both atoms. Hence, option (C) is correct.

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Answer:

Thus 1 Ampere is the current is defined as flow of 1 coulomb charge through a conductor in 1 second.

Explanation:

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Answer

?????

Explanation:

Answer:

Average speed is 60 km/hr whereas average velocity is 0 km/ hr.

Explanation:

The average speed of the boat is 60 km/ hr while on the other hand, the average velocity of the boat is 0 km/ hr because average speed is the total distance covered by the boat in total time and average velocity is the displacement covered by the boat in total time. The total distance covered by the boat is 60 km and the total time is 60 minutes which is equals to one hour so the answer is 60 km/hr whereas the displacement is the shortest distance between initial and final position which is 0 in this case so 0 divided by 60 minutes or one hour is also 0.

Answer:

The first option- Sun shining through clouds

Explanation:

Answer:

please put a picture, i dont know what you are doing so i cant help.

Explanation:

Answer:

""gravity. the force that pulls on objects and causes acceleration if the objects are not balanced by an opposing force. speed. distance traveled per unit time. Newton's Second Law of Motion.""

Explanation:

Answer:

pH value is between 6.5 and 6.8

Explanation:

Explanation:

Milk fresh from the cow typically has a pH between 6.5 and 6.7. The pH of milk changes over

Answer:

Sam's average velocity for the entire walk is approximately;

0.075 km/min

Explanation:

The given parameters of the Lake Loop Trail are;

The distance of the trail Sam takes his dog to walk around = 5-km

From the table for the position and time, we have;

[tex]\begin{array}{ccc}Position \ (km) &&Time \ (min)\\0&&0\\1&&12\\2&&22\\3&&33\\4&&54\\5&&67\end{array}[/tex]

Plotting the given points gives the attached chart created with Microsoft Excel

The coordinates of the points are A(0,0), B(67, 5), C(67, 0)

By the definition of average velocity, we have;

[tex]Average \ velocity = \dfrac{Total \ distance}{Total \ time \ taken}[/tex]

From the plot of the points therefore, we have;

[tex]Average \ velocity= \dfrac{Length \ of BC}{The \ time \ elapsed \ between \ AC} = \dfrac{5 \ km - 0 \ km}{67 \ min - 0 \ min} = \dfrac{5 \ km}{67 \ min} \approx 0.075 \ km/min[/tex]Therefore;

Sam walked at an average velocity of approximately 0.075 km/min.

Answer:

They travel

Explanation:

Because they move in a certin way

Answer:

1. (a) The final velocity is 20 m/s

(b) The distance travelled is20 meters

2. The distance travelled by the train in the 30 seconds is 825 meters

3. The most correct option is;

(d) 53 km

4. The heat, developed by the electric iron is 15,000 joules

5. a) In the first network the resistance between A and B is 2 Ω

b) In the second network the resistance between A and B is 4Ω

c) In the third network the resistance between A and B is 6Ω

d) In the fourth network the resistance between A and B is 2Ω

Explanation:

1. (a) The parameters of the cheetahs motion are;

The initial motion (velocity) of the cheetah = 0 m/s (The cheetah starts from rest)

The acceleration of the cheetah, a = 2 m/s²

The duration of the acceleration of the cheetah, t = 10 seconds

The kinematic equation of the motion of uniform acceleration, of the cheetah can be written in the following form;

v = u + a·t

s = u·t + 1/2·a·t²

Where;

v = The final velocity

u = The initial velocity = 0 m/s

a = The acceleration of the cheetah = 2 m/s²

s = The distance traveled

∴ v = 0 + 2 × 10 = 20

The final velocity, v = 20 m/s

(b) From s = u·t + 1/2·a·t², we have;

s = 0 × 10 + 1/2 × 10 × 2² = 20

The distance travelled, s = 20 meters

2. The given details of the motion of the train are;

The initial velocity of the train, u = 20 m·s⁻¹

The acceleration of the train, a = 0.5 m·s⁻²

The duration of the train's acceleration, t = 30 seconds

Therefore, the distance travelled, 's', is given by; s = u·t + 1/2·a·t²

∴ s = 20 × 30 + (1/2) × 0.5 × 30² = 825

The distance travelled by the train in the 30 seconds, s = 825 meters

3. The given distance the truck covers with the average speed of 80 km/h, d₁ = 40 km

The distance the truck then covers with the average speed of 40 km/h, d₂ = 40 km

[tex]Average \ speed = \dfrac{Total \ distance}{Time}[/tex]

[tex]\therefore time, \, t = \dfrac{Total \ distance}{Average \ speed}[/tex]

The time it takes the truck to cover the 40 km at 80 km/h = 40 km/(80 km·h) t₁ = 0.5 hour

The time it takes the truck to cover the 40 km at 80 km/h = 40 km/(40 km·h) t₂ = 1 hour

The total time taken to cover both 40 km distances, t = t₁ + t₂

∴ The total time taken to cover both 40 km distances, t = (0.5 + 1) hour = 1.5 hours

The total distance covered at both speeds, d = d₁ + d₂

∴ d = 40 km + 40 km = 80 km

The average speed of the truck for the total distance, [tex]v_{average}[/tex] = d/t

∴ [tex]v_{average}[/tex] = 80 km/1.5 hours = 53.[tex]\overline 3[/tex] km/h ≈ 53 km/h

The average speed of the truck for the total distance, [tex]v_{average}[/tex] ≈ 53 km/h

The correct option is (d) 53 km

4. The heat, 'H', developed by the electric iron is given by the following formula;

H = I²·R·t

Where;

I = The current flowing in the electric iron = 5 A

R = The resistance of the iron = 20Ω

t = The time duration of the flow of the current = 30 s

∴ H = (5 A)² × 20 Ω × 30 s = 15,000 joules

The heat, developed by the electric iron, H = 15,000 joules

5. Let 'R' represent the resistance between A and B in each network

a) For the first network, we have;

1/R = 1/(2 + 2) + 1/(2 + 2) = 1/4 + 1/4 = 1/2

∴ R = 2 Ω

∴ The resistance between A and B is 2 Ω

b) For the second network, we have;

R = 1/(1/2 + 1/2) + 3 = 4

R = 4Ω

∴ The resistance between A and B is 4 Ω

c) For the third network, we have;

R = 2 + 1/(1/4 + 1/4) + 2 = 6

R = 6Ω

∴ The resistance between A and B is 6 Ω

d) For the fourth network, we have;

R = 1/(1/2 + 1/2) + 1/(1/2 + 1/2) = 2

R = 2Ω

∴ The resistance between A and B is 2 Ω

Answer:

3V

Explanation:

From the question given above, we can see clearly that the resistors are arranged in parallel connection. Hence, the same voltage will pass through the resistors i.e

Total voltage = voltage of 3 Ω = voltage of 6 Ω

From the question given above,

The total voltage = 3 V

Therefore,

Voltage of 3 Ω = total voltage

Voltage of 3 Ω = 3V

Thus, option 3 gives the correct answer to the question.

Answer:

t = 0.28 seconds

Explanation:

Given that,

Force acting on a firework, F = 700 N

The momentum of the firework, p =200 kg-m/s

We need to find the time before it explodes. Ket the time be t. We know that, the rate of change of momentum is equal to external frce. So,

[tex]F=\dfrac{P}{t}\\\\t=\dfrac{P}{F}\\\\t=\dfrac{200}{700}\\t=0.28\ s[/tex]

So, the required time is equal to 0.28 seconds.

Answer:

40.6°

Explanation:

The angle of refraction, when light passes from air into water at an angle of 60° from the normal, is 40.6°

It states that the ratio of sine of angle of incidence and angle of refraction is equal to the refractive index of second medium to the first medium.

sini/sinr =n₂ / n₁

Given, the light passes from air into water at an angle of 60° from the normal, the angle of incidence i = 60°, refractive index of air n₁ =1, refractive index of water n₂ = 1.333, then the angle of refraction is

sinr = sini x (n₁/n₂)

Plug the values, we get

sinr = sin60 x (1/1.333)

sinr = 40.6°

The angle of refraction is less than angle of incidence due to refraction.

Thus, the angle of refraction is 40.6°

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Answer:

The speed of the student just before she lands, v₂ is approximately 8.225 m/s

Explanation:

The given parameters are;

The mass of the physic student, m = 43.0 kg

The height at which the student is standing, h = 12.0 m

The radius of the wheel, r = 0.300 m

The moment of inertia of the wheel, I = 9.60 kg·m²

The initial potential energy of the female student, P.E.₁ = m·g·h₁

Where;

m = 43.0 kg

g = The acceleration due to gravity ≈ 9.81 m/s²

h = 12.0 h

∴ P.E.₁ = 43 kg × 9.81 m/s² × 12.0 m = 5061.96 J

The kinetic rotational energy of the wheel and kinetic energy of the student supporting herself from the rope she grabs and steps off the roof, K₁, is given as follows;

[tex]K_1 = \dfrac{1}{2} \cdot m \cdot v_{1}^2+\dfrac{1}{2} \cdot I \cdot \omega_{1}^2[/tex]

The initial kinetic energy, 1/2·m·v₁² and the initial kinetic rotational energy, 1/2·m·ω₁² are 0

∴ K₁ = 0 + 0 = 0

The final potential energy of the student when lands. P.E.₂ = m·g·h₂ = 0

Where;

h₂ = 0 m

The final kinetic energy, K₂, of the wheel and student is give as follows;

[tex]K_2 = \dfrac{1}{2} \cdot m \cdot v_{2}^2+\dfrac{1}{2} \cdot I \cdot \omega_{2}^2[/tex]

Where;

v₂ = The speed of the student just before she lands

ω₂ = The angular velocity of the wheel just before she lands

By the conservation of energy, we have;

P.E.₁ + K₁ = P.E.₂ + K₂

∴ m·g·h₁ + [tex]\dfrac{1}{2} \cdot m \cdot v_{1}^2+\dfrac{1}{2} \cdot I \cdot \omega_{1}^2[/tex] = m·g·h₂ + [tex]\dfrac{1}{2} \cdot m \cdot v_{2}^2+\dfrac{1}{2} \cdot I \cdot \omega_{2}^2[/tex]

Where;

ω₂ = v₂/r

∴ 5061.96 J + 0 = 0 + [tex]\dfrac{1}{2} \times 43.0 \, kg \times v_{2}^2+\dfrac{1}{2} \times 9.60 \, kg\cdot m^2 \cdot \left (\dfrac{v_2}{0.300 \, m} }\right ) ^2[/tex]

5,061.96 J = 21.5 kg × v₂² + 53.[tex]\overline 3[/tex] kg × v₂² = 21.5 kg × v₂² + 160/3 kg × v₂²

v₂² = 5,061.96 J/(21.5 kg + 160/3 kg) ≈ 67.643118 m²/s²

v₂ ≈ √(67.643118 m²/s²) ≈ 8.22454363 m/s

The speed of the student just before she lands, v₂ ≈ 8.225 m/s.

Answer:

a = 4 m/s²

Explanation:

Given: 28 N, 7 kg

To find: Acceleration (a)

Solution: To find (a), divide force by weight

A = F ÷ m

=  28 ÷  7

= 4 m/s²

Newtons are derived units, equal to 1 kg-m/s². In other words, a single Newton is equal to the force needed to accelerate one kilogram one meter per second squared.

Answer:

Ok.............

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Answer:

In a machine, friction reduces the mechanical advantage, or the ratio of output to input: an automobile, for instance, uses one-quarter of its energy on reducing friction. Yet, it is also friction in the tires that allows the car to stay on the road, and friction in the clutch that makes it possible to drive at all

Explanation:

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