In which of these cases is a waiter doing work on the object

Which of the following describes the effect of a convex mirror on light rays?

natulia [17]

B. It reflects light rays outward.

A convex mirror looks like this ⊂. So when light rays hit the outward curves, it bends the light rays outwards, and backwards, and it would appear to be coming from its center called the focus.

3 0

3 years ago

Select all that apply to electrons and energy levels. - Scientists have not yet determined exactly why electrons do not collapse

Elenna [48]

Answer:

- The limitation of the maximum number of electrons in a given energy level can be used to account for the periodic recurrence of properties as the number of electrons increases.

Explanation:

First - Scientists have not yet determined exactly why electrons do not collapse into the nucleus. FALSE: Scientists do know why electrons do not collapse. Since the beginins of quantum mechanics it's known that the energy at small scales is quantized, that means there only can be certain values meaning that the energy do not change continously. In the case of the electron, it can only have certain levels of energy, that means they do not radiate continously as the go arround the atom, instead it is only allowed to have a certain amount of energy in a given state therefore it can not lose energy continously collapsing into the nucleus.

Second - Electrons cannot be located between levels except when they are in the process of moving. FALSE: We can not say that a electron moves between energy levels, it only can exist in any of the levels, but never in between. Also, the electron in any of its possible energy lavels can not be located with complete certainty due to the uncertainty principle.

Fourth - Electrons have any random energy. FALSE: as exposed above the electrons can only have certain cuantized energy levels acordinly to the rules of quantum physics

Fifth - Electrons can be found between energy levels. FALSE: Like said before we can not say that a electron exists between energy levels, it only can exist in any of the allowed levels, but never in between.

Thirth (correct one) : - The limitation of the maximum number of electrons in a given energy level can be used to account for the periodic recurrence of properties as the number of electrons increases. TRUE: the maximum number of electrons allowed in a given energy level directly determines the tipe of bond an atom can made with another (this due to the number of electrons in the higest energy level), so for example the elements in the left of a given row of the periodic table tend to have ionic bonds, but in the other hand the elements on right side tend form more covalent bonds. And this characteristic directly correllate with diferent properties of the elements.

7 0

3 years ago

“instrucciones” para hacer los diagramas de Lewis de un compuesto iónico y luego para uno covalente. ¿En qué se diferencian y en

Mazyrski [523]

Answer:

- Se diferencian en que en los compuestos iónicos se ceden y aceptan electrones, mientras que en los covalentes de comparten.

- Se parecen en que los enlaces son formados por medio de los electrones de valencia y que en ambos compuestos la ley del octeto se debe cumplir.

Explanation:

¡Hola!

En este caso, debemos recordar que los compuestos iónicos se dan cuando se forman enlaces iónicos en los que el elemento más electronegativo tiene la capacidad de aceptar los electrones perdidos por el elemento menos electronegativo con el fin de cumplir la ley del octeto en la que 8 electrones deben ser exhibidos en la molécula. Por otro lado, los compuestos covalentes se forman cuando los átomos comparten sus electrones de valencia con el fin de alcanzar la ley del octeto.

De este modo encontramos que se diferencian en que en los compuestos iónicos se ceden y aceptan electrones, mientras que en los covalentes de comparten.

Por otro lado, ambos se parecen en que los enlaces son formados por medio de los electrones de valencia y que en ambos compuestos la ley del octeto se debe cumplir.

¡Saludos!

6 0

3 years ago

Need help ASAP please help me please

lbvjy [14]

Answer:

145

Explanation:

5 0

2 years ago

Near the end of a marathon race, the first two runners are separated by a distance of 45.0 m. The front runner has a velocity of

xxMikexx [17]

Answer:

a. 0.7 m/s

b. The second runner

c. 4.20 meters

Explanation:

a. To know the relative speed we can use the following equation:

Relative Speed (Vr) = V1 - V2

The relative speed is used to compared the velocity of one object (V1) to another object (V2). To learn the Relative Velocity from the second runner to the first we do the following:

Relative Speed (Vr) = Second Runner Velocity (Vs) - First Runner Velocity (Vf)

Vr = 4.20 m/s - 3.50 m/s

Vr = 0.7 m/s

This means that the second runner is gaining 0.7 meter from the first runner each second.

b. To know which runner will gain the race, we need to keep in mind, that the seconds runner is 45 meter more away that the first runner from the goal. Knowing this, the winner will be the one that reach the goal on less time.

Because movement is constant, we can use the following equation:

Velocity (V) = Distance (D) / Time (T)

To get the time we do:

T = D / V

Now, for the first runner:

T = 250 meters / (3.50 m/s)

T = 71.42 seconds

For the second runner.

T = (250 meters + 45 meters) / (4.20 m/s)

T = 70,23 seconds

Because the second runner takes less time to reach the goal, he wins the race.

c. Because it is know how much time takes the winner to get to the finish line, we can use that same time to know how far was the first runner from the goal. This is posible we know that how far he is from the goal is as follows.

Distance from goal (Dg) = Total Distance (D) - Distance travelled (Dt)

Where Total Distance (D) is 250 mts. And the distance travelled can be obtained by using the following equation.

Velocity (V) = Distance (D) / Time (T)

Searching for distance:

D = V / T.

D = (3.50 m/s) * 70.23 s

D = 245,80 meters

Soo

Distance from goal (Dg) = Total Distance (D) - Distance travelled (Dt)

Dg = 250 meters - 245,80 meters

Dg = 4,20 meters

The first runner was 4,20 meter behind the second one when the second runner crossed the goal

3 0

3 years ago

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